Zootaxa, Larval morphology of Rhantus Dejean, 1833ocean.otr.usm.edu/~w777157/Dytiscid symposium/Rhantus.pdf · Larval morphology of Rhantus Dejean, 1833 (Coleoptera: Dytiscidae: Colymbetinae):

Accepted by I. Ribera: 8 Oct. 2009; published: 22 Dec. 2009

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Zootaxa 2317: 1–102 (2009) www.mapress.com/zootaxa/ Monograph

ZOOTAXA

Larval morphology of Rhantus Dejean, 1833 (Coleoptera: Dytiscidae: Colymbetinae):

descriptions of 22 species and phylogenetic considerations

YVES ALARIE1, MARIANO C. MICHAT2, ANDERS N. NILSSON3, MIGUEL ARCHANGELSKY4 & LARS HENDRICH5

1Department of Biology, Laurentian University, Ramsey Lake Road, Sudbury, Ontario, Canada. E-mail: [email protected]

2CONICET Laboratorio de Entomología, DBBE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Av. Int. Güiraldes s/n, Ciudad Universitaria, 1428 Buenos Aires, Argentina. E-mail: [email protected]

3Department of Ecology and Environmental Science, University of Umeå, Sweden. E-mail: [email protected], Laboratorio de Investigaciones en Ecología y Sistemática Animal, Universidad Nacional de La Patagonia, San

Juan Bosco, Sarmiento 849, 9200, Esquel, Chubut, Argentina. E-mail: [email protected] Staatssammlung, Münchhausenstraße 21, D - 81247 München, Germany. E-mail: [email protected]

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ALARIE ET AL.2 · Zootaxa 2317 © 2009 Magnolia Press

Yves Alarie, Mariano C. Michat, Anders N. Nilsson, Miguel Archangelsky & Lars HendrichLARVAL MORPHOLOGY OF RHANTUS DEJEAN, 1833 (COLEOPTERA: DYTISCIDAE: COLYMBETINAE): DESCRIPTIONS OF 22 SPECIES AND PHYLOGENETIC CONSIDERATIONS(Zootaxa 2317)

102 pp.; 30 cm.

22 Dec. 2009

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ISSN 1175-5326 (Print edition)

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Zootaxa 2317 © 2009 Magnolia Press · 3LARVAE OF THE GENUS RHANTUS

Table of contents

Abstract ............................................................................................................................................................................... 3Introduction ......................................................................................................................................................................... 4Material and methods .......................................................................................................................................................... 4Description of the larvae of Rhantus Dejean, 1833 ............................................................................................................ 6Key to species of instar I and III of the genus Rhantus ................................................................................................... 19

Description of larvae of Rhantus antarcticus nahueli Trémouilles, 1984 ................................................................. 23Description of larvae of Rhantus anisonychus Crotch, 1873..................................................................................... 25Description of larvae of Rhantus binotatus (Harris, 1828) ........................................................................................ 26Description of larvae of Rhantus calidus (Fabricius, 1792) ....................................................................................... 27Description of larvae of Rhantus calileguai Trémouilles, 1984 ................................................................................ 29Description of larvae of Rhantus capensis (Aubé, 1838) .......................................................................................... 30Description of larvae of Rhantus consputus (Sturm, 1834) ...................................................................................... 31Description of larvae of Rhantus exsoletus (Forster, 1771) ....................................................................................... 32Description of larvae of Rhantus fennicus Hulden, 1982 ......................................................................................... 34Description of larvae of Rhantus frontalis (Marsham, 1802) .................................................................................... 35Description of larvae of Rhantus grapii (Gyllenhal, 1808) ...................................................................................... 36Description of larvae of Rhantus latitans Sharp, 1882 .............................................................................................. 37Description of larvae of Rhantus notaticollis (Aubé, 1837) ...................................................................................... 38Description of larvae of Rhantus orbignyi Balke, 1992 ............................................................................................. 40Description of larvae of Rhantus phocaenarum Guignot, 1957 ................................................................................ 42Description of larvae of Rhantus signatus (Fabricius, 1775) ..................................................................................... 46Description of larvae of Rhantus simulans Régimbart, 1908 .................................................................................... 47Description of larvae of Rhantus socialis (C. O. Waterhouse, 1876) ........................................................................ 48Description of larvae of Rhantus suturalis (Macleay, W.S., 1825) ............................................................................ 49Description of larvae of Rhantus suturellus (Harris, 1828) ....................................................................................... 50Description of larvae of Rhantus validus Sharp, 1882 ............................................................................................... 52Description of larvae of Rhantus wallisi Hatch, 1953 ............................................................................................... 53

Character Analysis ............................................................................................................................................................ 54Discussion ......................................................................................................................................................................... 54Acknowledgements ........................................................................................................................................................... 56References ......................................................................................................................................................................... 56

Abstract

Descriptions of larval instars of 22 species of Rhantus Dejean, 1833 are presented including a detailed chaetotaxicanalysis of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. A parsimony analysisincluding 25 Rhantus species (the 22 species described in this paper + 3 additional ones) from all major zoogeographicregions and representatives of other Colymbetini genera was conducted using the program TNT based on 43 informativelarval characteristics. Jackknife values indicate strong support for the monophyly of members of the tribe Colymbetini(Colymbetinae), which is supported by eight synapomorphies. It is postulated that Rhantus is polyphyletic as Rhantus(Nartus) grapii (Gyllenhal, 1908) and R. monteithi Balke, Wewalka, Alarie & Ribera, 2007 occur as more closely relatedphylogenetically to other genera of the tribe Colymbetini than to the Rhantus species studied. We suggest that theNeotropical species R. orbignyi Balke, 1992, R. antarcticus nahueli Trémouilles, 1984, R. calidus (Fabricius, 1792) andR. validus Sharp, 1882 represent a distinct lineage within the Colymbetini. All these species diverge at the basis of thestrict consensus trees prior to all other Colymbetini studied and are characterized by several unique larval characterstates. Larvae of Palearctic and Nearctic species of Rhantus were found to share similar character states, which issuggestive of a common phylogenetic origin.

Key words: �Dytiscidae, Colymbetini, Rhantus, larval morphology, chaetotaxy, phylogeny



Introduction

The dytiscid genus Rhantus Dejean, 1833 is comprised of about 100 species worldwide (Nilsson 2001) and isrepresented in all major zoogeographic regions as well as on many oceanic islands. These beetles occur inshallow, plant-lined margins of pools and marshy areas (Zimmerman & Smith 1975). In term of classification,Rhantus is treated as a member of the subfamily Colymbetinae, which contains three tribes and 10 generaworldwide: Anisomeriini (Anisomeria Brinck, 1943, Senilites Brinck, 1948), Carabdytini (Carabdytes Balke,Hendrich & Wewalka, 1992) and Colymbetini (Rhantus, Bunites Spangler, 1972, Hoperius Fall, 1927,Melanodytes Seidlitz, 1887, Neoscutopterus J. Balfour-Browne, 1943, Colymbetes Clairville, 1806,Meladema Laporte, 1835) (Nilsson 2001). Due largely to the great diversity of the Colymbetinae, intergenericrelationships of members of the subfamily are not well known. Recent studies on larval morphology of thesetaxa, however, suggest a close phylogenetic relationship of Rhantus with members of Meladema andNeoscutopterus (Alarie & Hughes 2006; Michat 2005). Nilsson & Hilsenhoff (1991) and Ribera et al. (2008)postulated that Rhantus probably is not a natural group.

Larval morphology of most Rhantus species is still poorly known. Worldwide, the larvae of 19 specieshave been described and/or figured, in most cases very superficially (Meinert 1901; Williams 1936; Bertrand1928; Galewski 1963; Watts 1963; James 1969; Barman 1972; Nilsson 1987; Costa et al. 1988; Klausnitzer1991; Alarie & Wang 2004; Balke et al. 2007). Except for R. fennicus Huldén, 1982 (Nilsson 1987), R.formosanus Kamiya, 1938 (Alarie & Wang 2004), R. monteithi Balke, Wewalka, Alarie & Ribera, 2007 and R.poellerbauerae Balke, Wewalka, Alarie & Ribera, 2007 (Balke et al. 2007), none of these descriptions usedchaetotaxy as a diagnostic feature.

Larval morphology is of great interest in the study of phylogenetic relationships of Holometabola. Asdifferent expressions of the same genotype, larval characters help to complement adult characters, which havebeen traditionally the primary basis for classification. Moreover, recent studies on larvae of Colymbetinaehave indicated the usefulness of larval chaetotaxy (Alarie 1995, 1998; Alarie & Balke 1999; Alarie et al.1998; Alarie & Hughes 2006; Michat 2005) both from a phylogenetic and diagnostic perspective.

This paper is meant to be a step towards a better knowledge of the larval morphology of the genusRhantus. It has the following goals: (1) descriptions of 22 species of Rhantus from all major zoogeographicregions with an emphasis on chaetotaxic analysis of the head capsule, cephalic appendages, legs, lastabdominal segment and urogomphi and (2) analysis of the phylogenetic position of Rhantus within theColymbetinae based on larval features.

Material and methods

Larvae examined. Description of the larval stages and taxonomic conclusions reported in this paper arebased on examination of larvae either found in association with adults or reared ex ovo (Alarie et al. 1989).

Preparation. Larvae were disarticulated and mounted on standard glass slides with Hoyer's medium.Microscopic examination at magnification of 80–1000X was done using both an Olympus BX50 compoundmicroscope equipped with Nomarsky differential interference optics and an Olympus CX31 compoundmicroscope. Figures were prepared through use of a drawing tube attached to the microscope. Voucherspecimens are deposited in the research collections of Y. Alarie and M.C. Michat.

Descriptions. A complete description applying to all species is provided under the treatment of the genus,but only shorter diagnoses/descriptions and comments on variation are provided under the treatment of eachspecies.

Measurements. All measurements were made with a compound microscope equipped with a micrometereyepiece. The part to be measured was adjusted so that it was, as nearly as possible, parallel to the plane of theobjectives. The following measures were taken: Head length (HL): total head length including thefrontoclypeus, measured medially along epicranial stem. Head width (HW): maximum head width. Length of



frontoclypeus (FRL): from apex of nasale to posterior margin of ecdysial suture. Occipital foramen width(OCW): maximum width measured along dorsal margin of occipital foramen. Coronal line length (COL):measured along midline. Length of mandible (MN): measured from laterobasal angle to apex. Width of MN:maximum width measured at base. Length of antenna (A), maxillary (MP) and labial (LP) palpi were derivedby adding the lengths of the individual articles; each article is denoted by the corresponding letter(s) followedby a number (e.g. A1: first antennomere; MP1: maxillary palpomere 1; LP1: labial palpomere 1). A3’ is usedas an abbreviation for the apical lateroventral process of third antennomere. Length of galea (GA): measuredalong dorsal mid-line. Length of leg (L1–L3) including the longest claw: derived by adding the lengths of theindividual articles. Length of trochanter includes only the proximal portion, the length of distal portion beingincluded in the femoral length. Dorsal length of last abdominal segment (LLAS): measured along midlinefrom anterior to posterior margin. Length of urogomphus (U): measured along outer margin. Thesemeasurements were used to calculate several ratios, which characterize body shape.

Chaetotaxic analysis. Primary (observed in instar I) and secondary (added throughout the ontogeneticdevelopment) setae and pores were distinguished on the head capsule, head appendages, legs, last abdominalsegment and urogomphus. The setae and pores were coded according to the system proposed by Alarie (1998)for the cephalic capsule and head appendages and Alarie (1995) for the last abdominal segment andurogomphus. Setae are coded by two capital letters corresponding to the first two letters of the name of thestructure on which the seta is located (AB, last abdominal segment; AN, antenna; CO, coxa; FE, femur; FR,frontoclypeus; LA, labium; MN, mandible; MX, maxilla; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia;TR, trochanter; UR, urogomphus) and a number. Pores are coded in a similar manner except that a lower caseletter replaces the number. The position of the sensilla is described by adding the following abbreviations: A,anterior; AV, anteroventral; D, dorsal; Di, distal; Pr, proximal; PV, posteroventral. Instar I larvae of species ofthe genus Rhantus are characterized by the presence of additional setae (i.e., primary setae restricted to agenus or a tribe, which are not included in the ground-plan pattern of the Dytiscidae) on femora, tibiae andtarsi (Alarie 1995). These additional setae were included in the count of secondary setae owing to inter- andintraspecific variability.

Colour. Description of colour is given from ethanol-preserved specimens unless otherwise stated.Parsimony analysis. Taxa were selected to give a broad overview of the morphological diversity found

within Rhantus. All 22 Rhantus species (Table 1) of which the larvae have been described in the present workplus those, which have been described in detail in other works (R. formosanus, R. monteithi and R.poellerbaurae) were included in the ingroup. In order to examine the phylogenetic value of the charactersobserved on the larvae of Rhantus and to test the relationships of this genus with other genera of the tribeColymbetini, a cladistic analysis was performed rooting the cladogram with representatives of othercolymbetine genera and selected genera of the subfamily Agabinae (Agabus Leach, Ilybius Erichson,Ilybiosoma Crotch) as it has been suggested that Agabinae could represent the sister-group of the cladeColymbetinae + Lancetinae + Dytiscinae (Miller 2001). Species were used as terminals to avoid anyassumption of monophyly of higher taxa.

The characters used (Table 2) and the distribution of character states among the terminal taxa (Table 3) arelisted. Apart from including the 43 informative characters we also have listed 15 autapomorphies. Althoughthese features do not assist in the resolution of the relationships between taxa, they still represent importantfacies by which terminal groups (i.e. species) can be recognized. The phylogenetic relationships of Rhantuswere analyzed cladistically using the program TNT (Goloboff et al. 2008). The tree was rooted in Agabusanthracinus Mannerheim, 1852 (Agabini), which was proposed to be closely related to Colymbetini (Miller2001). All characters were treated as unordered and equally weighted. Multistate characters (characters 37,38, 41, 46, 49, 50, 51) were treated as nonadditive. A heuristic search was implemented using ‘tree bisectionreconnection’ as algorithm, with 200 replicates and saving 100 trees per replication (previously setting ‘hold20000’). A second analysis was also performed with the same parameters, but using implied weighting (an aposteriori weighting) with the default options of TNT (K = 3). Bremer support values were calculated usingthe commands ‘hold 20000’, ‘sub n’ and ‘bsupport’, where ‘n’ is the number of extra steps allowed. The



process was repeated increasing the length of the suboptimal cladograms by one step, until all Bremer valueswere obtained (Kitching et al. 1998). Jackknife values were calculated with 2000 replicates and P (removalprobability) = 36.

TABLE 1. List of species of Rhantus of which larvae were studied; AF, Afrotropical; AU, Australian; NA, Nearctic; NT,

Neotropical; OR, Oriental; PA, Pacific; PL, Palearctic. The species code and larval instar are indicated.

1 Alarie & Wang (2004); 2 Balke et al. (2007)

Description of the larvae of Rhantus Dejean, 1833

Diagnosis. One important conclusion of this paper is that Rhantus is polyphyletic. It is therefore impossible topropose any diagnostic larval characters that may help at distinguishing members of Rhantus from otherColymbetini genera. Larvae of a majority of Rhantus species (19 of 24 species studied), however, differ fromthose of other Colymbetini by having urogomphus fractured proximally.

Species Distribution Code Instars

R. anisonychus Crotch, 1873 NA, NT ANI I II III

R. antarcticus nahueli Trémouilles, 1984 NT ANT I II III

R. binotatus (Harris, 1828) NA BIN I II III

R. calileguai Trémouilles, 1984 NT CAG I II III

R. calidus (Fabricius, 1792) NA, NT CAL I II III

R. capensis (Aubé, 1838) AF CAP III

R. consputus (Sturm, 1834) PL CON I II III

R. exsoletus (Forster, 1771) PL EXS I II III

R. fennicus Huldén, 1982 PL FEN I II III

R. formosanus Kamiya, 19381 PL FOR II III

R. frontalis (Marsham, 1802) PL FRO II III

R. grapii (Gyllenhal, 1808) PL GRA I II III

R. latitans Sharp, 1882 PL LAT III

R. monteithi Balke et al., 20072 PA MON III

R. notaticollis (Aubé, 1837) PL NOT I II III

R. orbignyi, Balke, 1992 NT ORB I II III

R. phocaenarum Guignot, 1957 AF PHO I II III

R. poellerbauerae Balke et al. 20072 PA POE III

R. signatus (Fabricius, 1775) NT SIG I II III

R. simulans Régimbart, 1908 AU SIM III

R. socialis (C. O. Waterhouse, 1876) AF SOC I II III

R. suturalis (Macleay, W.S.,1825) AU, OR, PL SUA III

R. suturellus (Harris, 1828) NA, PL SUE I II III

R. validus Sharp, 1882 NT VAL I II III

R. wallisi Hatch, 1953 NA WAL I II III



TABLE 2. Characters used for the phylogenetic analysis and the coding of states using selected genera of Agabinae and

Colymbetinae as outgroups.

Character States

Head capsule

01 Frontoclypeus (instar I) 0 – lacking additional setae1 – with additional setae

02 Pore FRe (instar I) 0 – absent1 – present

03 Parietale (instar I) 0 – lacking additional setae1 – with additional setae

04 Occipital carina (instar I) 0 - lacking1 - present

05 Frontoclypeus (instar I) 0 – at most extending at level of tip of adnasaliae1 – extending beyond tip of adnasaliae

06 Adnasaliae (instar I, II, III) 0 – converging inward1 – diverging outward

Head appendages

07 Antennomere I, pore ANg (instar I) 0 – proximal1 – median to apical

08 Antennomere I (instar III) 0 – lacking secondary setae1 – with secondary setae

09 Antennomere II (instar III) 0 – lacking secondary setae1 – with secondary setae

10 Antennomere III, lateral projection (A3')(instar III)

0 – finger-like1 – hole- to bulge-like

11 Antennomere III, ventroapical spinula(instar I, II, III)

0 – present1 – absent

12 Antennomere III, additional ventroapicalpores (instar I)

0 – absent1 – present

13 Antenna (instar I) 0 – microspinulae absent1 – microspinulae over most of its surface

14 Antennomeres 2– 4 (instar III) 0 – not fractured proximally1 – fractured proximally

15 Maxillary palpus (instar III) 0 – less than 1.60 times length of labial palpus1 – about 2.00 times length of labial palpus

16 Maxillary palpomere I (instar III) 0 – lacking secondary setae1 – with secondary setae

17 Maxillary palpomeres 2– 3 (instar III)

0 – not fractured proximally1 – fractured proximally

18 Primary seta MX5 (instar I) 0 – short, much shorter than labial palpomere I1 – elongate, longer than labial palpomere I

19 Stipes (instar I) 0 – lacking additional setae along inner margin1 – with at least 1 additional seta along inner margin

20 Galea (instar III) 0 – short, ‹ 0.50 times length of maxillary palpomere 12 – elongate, › 0.70 times length of maxillary palpomere 1

21 Stipes (instar III) 0 – with short setae along inner margin1 – with three elongate setae along inner margin

continued next page



TABLE 2. (continued)

Character States

22 Maxillary palpus (instar I) 0 – microspinulae lacking1 – microspinulae over most of dorsal surface

23 Mandible, additional setae (instar I) 0 – absent1 – present

24 Mandible (instar III) 0 – less than 3.40 times as long as broad1 – more than 4.00 times as long as broad

25 Anterior margin of prementum (instar I,II, III)

0 – straight to shallowly emarginated1 – deeply emarginated

26 Labial palpomere 2 (instar III) 0 – not fractured proximally1 – fractured proximally

27 Labial palpus (instar I) 0 – microspinulae lacking1 – microspinulae over most of dorsal surface

28 Prementum AD primary setae (instar I,II, III)

0 – minute to short1 – elongate

Legs

29 Procoxal seta CO7 (instar I) 0 – inserted more proximally, anterior to seta CO61 – inserted more distally, at about level of seta CO6

30 Metatrochanter (Instar III) 0 – with < 14 secondary setae1 – with > 16 secondary setae

31 Trochanter (instar I) 0 – lacking additional setae1 – with additional setae

32 Seta FE1 (instar I) 0 – inserted distally1 – inserted proximally

33 Femur (instar I) 0 – lacking additional setae along dorsal margin 1 – with additional setae along dorsal margin

34 Mesofemoral seta FE5 (instar I) 0 – short and spine-like1 – elongate and hair-like

35 Metafemoral seta FE5 (instar I) 0 – short, spine-like1 – elongate and hair-like

36 Seta FE6 (instar I) 0 – short1 – elongate

37 Protibia (instar I) 0 – additional setae absent1 – additional setae on ventral margin only2 – additional setae on dorsal and ventral margins

38 Mesotibia (instar I) 0 – additional setae absent1 – additional setae on ventral margin only2 – additional setae on dorsal and ventral margins

39 Seta TI6 (instar I) 0 – short and spine-like1 – elongate and hair-like

40 Seta TI7 (instar I) 0 – short and spine-like1 – elongate and hair-like

41 Tarsus (instar I) 0 – additional setae absent1 – with 1 V additional seta2 – with at least 2 V additional setae

continued next page




Character States

42 Metafemur (instar I) 0 – lacking PV additional setae1 – with at least 1 PV additional seta

43 Tarsal claw basoventral microspinulae(instar I)

0 – absent1 – present

44 Meso- and metatibial ventral marginalspinulae (instar III)

0 – well developed 1 – weakly developed or lacking

45 Meso- and metatarsal ventral marginalspinulae (instar III)

0 – well developed 1 – weakly developed or lacking

46 Legs, natatory setae (instar II and III) 0 – lacking1 – on tibiae and tarsi2 – on femora, tibiae, and tarsi

Abdomen

47 Abdominal segment 7 (instar 1) 0 – membranous ventrally1 – sclerotized ventrally

48 Abdominal segment 8 (instar I) 0 – additional setae absent1 – additional setae present

Urogomphus

49 Urogomphus (instar III) 0 – subequal to HW1 – < 0.80 times HW2 – 1.20– 2.00 times HW3 – > 2.00 times HW

50 Urogomphus outer margin (Instar II, III) 0 – lacking secondary setae1 – with predominantly elongate hair-like setae 2 – with a variable number of spiniform and hair-likesecondary setae3 – with spiniform secondary setae only

51 Urogomphus inner margin (instar II, III) 0 – lacking secondary setae1 – with secondary setae along outer margin only2 – with secondary setae along both inner and outer margins

52 Urogomphus (instar III) 0 – not fractured proximally1 – fractured proximally

53 Urogomphus (instar I, II, III) 0 – two segmented1 – one segmented

54 Urogomphus (instar I) 0 – at most with 1 additional seta1 – with several additional setae

55 Primary seta UR2 (instar I) 0 – about as long as seta UR31 – longer than seta UR3

56 Primary seta UR4 (instar I) 0 – shorter than setae UR5, UR6, UR81 – as long or longer than setae UR5, UR6, UR8

57 Primary seta UR5 (instar I) 0 – articulated posterior to seta UR71 – articulated anterior to seta UR7

58 Primary seta UR7 (instar I) 0 – shorter than setae UR5, UR6, UR81 – as long or longer than setae UR5, UR6, UR8



TABLE 3. Distribution of 58 larval morphological characters among species. Character states are scored 0-3, ?

(undetermined), - (inapplicable). Refer to Table 2 for character descriptions.

* From De Marzo (1974)

First-instar larva(Figs 1–14, 20–24, 30–34, 40–44, 51–55, 66–70, 76–80, 86–90, 101–106, 117–121, 127–131, 137–141, 147–151, 162–166, 177–181, 187–195, 201–205)

Characters

Taxon 1–5 6–10 11–15 16–20 21–25 26–30 31–35 36–40 41–45 46–50 51–58

Rhantus anisonychus Crotch 01011 01001 01100 00000 01000 01010 01011 11111 11100 20022 21100000

Rhantus antarcticus (Germain) 00011 01001 01000 00000 00000 00010 01000 10110 00100 20000 01100101

Rhantus binotatus (Harris) 01011 01001 01100 00000 01000 01000 01011 11111 11100 20022 21100000

Rhantus calileguai Trémouilles 01011 01001 01000 00000 00000 01010 01011 11111 11100 20022 21100000

Rhantus calidus (Fabricius) 00011 01001 01010 01010 10000 10110 01000 10010 00100 20010 00100010

Rhantus capensis Aubé ????? 01001 0??00 00?00 0??00 0?0?0 ????? ????? ???00 2??22 211?????

Rhantus consputus (Sturm) 01011 01001 01000 00000 00000 00010 01011 11111 11100 20001 21100100

Rhantus exsoletus (Forster) 01011 01001 01000 00010 00000 00010 01011 11111 11100 20021 21100100

Rhantus fennicus Huldén 01011 01001 01000 00000 00000 00000 01011 11111 21100 20001 21100100

Rhantus formosanus Kamiya ????? 01001 0??00 00?00 0??00 0?0?0 ????? ????? ???11 2??03 211?????

Rhantus frontalis (Marsham) ????? 01001 0??00 00?00 0??00 0?0?0 ????? ????? ???00 2??22 211?????

Rhantus grapii (Gyllenhal) 01000 11001 11000 00101 01000 01100 01111 11111 20111 20011 20101100

Rhantus latitans Sharp ????? 01001 0??00 00?00 0??00 0?0?0 ????? ????? ???00 2??01 211?????

Rhantus monteithi Balke et al. ????? 01001 0??00 00?00 0??00 0?0?0 ????? ????? ???10 2??11 1?1?????

Rhantus notaticollis (Aubé) 01011 01001 01000 00000 00000 00010 01011 11111 11100 20001 21100100

Rhantus orbignyi Balke 00011 01001 01000 00000 00000 00010 01000 10010 00100 20010 01100100

Rhantus phocaenarum Guignot 01011 01001 01000 00000 00000 00010 01011 11111 11100 20022 21100001

Rhantus poellerbauerae Balke et al. ????? 01001 0??00 00?00 0??00 0?0?0 ????? ????? ???11 2??10 001?????

Rhantus signatus (Fabricius) 01011 01001 01000 00000 00000 00010 01011 11111 11100 20022 21100000

Rhantus simulans Régimbart ????? 01001 0??00 00?00 0??00 0?0?0 ????? ????? ???00 2??01 211?????

Rhantus socialis (C. O. Waterhouse) 01011 01001 01000 00000 00000 00000 01011 11?11 11110 20022 21100000

Rhantus suturalis (Macleay) ????? 01001 01?00 00?00 00?00 0?0?0 ????? ????? ???00 2??21 211?????

Rhantus suturellus (Harris) 01011 01001 01000 00000 00000 00010 01011 12211 21100 20001 21100100

Rhantus validus Sharp 00011 01001 01000 00010 10000 00110 01000 10011 00100 20011 2011????

Rhantus wallisi Hatch 01011 01001 01000 00000 00000 00010 01011 12211 21100 20001 21100100

Agabus anthracinus Mannerheim 00000 00000 00000 00010 00000 00000 00000 00000 00000 00000 0000----

Ilybiosoma seriatum Say 00000 00000 00000 00010 00000 00000 00000 00000 00000 00000 0000----

Ilybius angustior Gyllenhal 00000 00000 00000 00010 00000 00000 00000 00000 00000 00000 0000----

Colymbetes dolabratus (Paykull) 01011 01001 01000 00000 00000 00010 01000 10011 00100 10001 20100000

Melanodytes pustulatus (Rossi)* 01011 0?001 ???00 00?00 1?000 0?110 010?0 10011 011?? 20011 20101101

Neoscutopterus hornii (Crotch) 11111 01001 11000 00000 00101 00011 01101 11111 21111 21111 2011????

Hoperius planatus Fall ?1??? 01111 01?01 10?00 00?10 00010 ????? ????? ??100 2??11 201?????

Meladema coriacea Laporte 11111 01001 01000 00010 00000 00011 01111 122?? 21111 20102 2011????

Meladema lanio (Fabricius) 11111 01001 01000 00010 00000 00011 11100 12201 21111 20103 2011????

Bunites distigma (Brullé) 11111 01??1 01?0? ??010 ??1?0 ??01? 01000 12211 211?? ?01?? ??11????

Carabdytes upin Balke et al. ????? 01001 0??00 00??0 0??00 0?0?1 ????? ????? ???10 2??23 201?????



Colour. Some species predominantly yellowish, others brown to greyish brown; head either without or withcolour pattern, remaining parts without colour pattern except for maculae variable in size and number onthoracic terga.

TABLE 4. Number and position of additional setae on the legs of instar I of selected species of Rhantus Dejean; AD =anterodorsal, AV = anteroventral, FE = femur, PV = posteroventral, TA = tarsus, TI = tibia; n = number of specimensstudied; acronyms as in Table 1.

Body. Subcylindrical.Head. Head capsule (Figs 1–2, 20, 30, 40, 51, 66, 76, 86, 101, 117, 127, 137, 147, 162, 177, 187, 201). HL

= 0.85–1.40 mm; HW = 0.78–1.44 mm; FRL = 0.38–0.67 mm. Flattened, subovate to subtrapezoidal, about asbroad as long (HL/HW = 0.88–1.13), maximum width at level of stemmata, constricted or not at level ofoccipital region; occipital foramen variable in width, HW/OCW = 1.44–2.55, deeply emarginate ventrally;ecdysial suture well-developed, coronal suture short, 0.46–0.59 times HL; occipital suture present, lightly orstrongly impressed; frontoclypeus subtriangular, lateral margins curved, apical margin convex mesally,extending at about level or beyond apex of lateral lobes [= adnasaliae], FRL/HL = 0.42–0.54, with one spine-like egg burster on each side (= ruptor ovi of Bertrand 1972), apical margin with 15–35 lamellae clypeales(Bertrand 1972) variable in shape (spiniform, digitiform or spatulate) and size; six stemmata, four on upperside of head and two on underside, arranged in two convex vertical series; tentorial pits visible ventrally oneach side of middle at about midlength; frontoclypeus and parietale covered with microspinulae or not.Antenna (Figs 3–4). Slender, either shorter or longer than HW (A/HW = 0.65–1.37); A1 the shortest, A4 thelongest or subequal to A3 (A4/A3 = 0.83–1.31); A3 with a ventroapical spinula present or lacking; apical

Species

Segment ANI(n= 3)

ANT(n= 2)

BIN(n= 2)

CAG(n= 3)

CAL(n= 1)

CON(n= 1)

EXS(n= 2)

FEN(n= 1)

GRA(n= 1)

NOT(n= 1)

ORB(n= 2)

PHO(n= 1)

SIG(n=3)

SOC(n= 3)

SUT(n= 2)

VAL(n= 2)

WAL(n= 2)

ProFE AD 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0

AV 1-2 5 3 1-2 1 4 5 5 2 3 4–5 3 2–3 1–2 3 3–4 4

PV 1 0 1 1 0 1 1 1 0 1 0 1 1 0–1 1 0–1 1

ProTI AD 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1

AV 2–3 0 1–2 1–2 0 2 2–3 3 3 2 0 2 2–3 1 2 0 2

PV 0 0 0 0 0 1 2 2 0 1 0 0 0 0 1 0 1–2

ProTA AV 1 0 1 1 0 1 1 1 2 1 0 1 1 1 1 0 1

PV 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 1

MesoFE AD 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0

AV 1–2 5 2–3 1 2 4 4–6 5 2 3 4–5 2 1–2 1–2 2–3 4–5 3

PV 1 0 0–1 1 0 1 1 1 0 1 0 1 1 1 1 0–1 1

MesoTI AD 0 0 0 0 0 0 0 0 0 0 0 0 0 0–1 1 0 1

AV 2–3 1 2–3 2 0 2 3–4 4 3 2 0 3 2–3 2–3 3 0 3

PV 0 0 0 0 0 1 2 2 0 1 0 0 0 0 1 0 1–2

MesoTA AV 1 0 1 1 0 1 1 1 3 1 0 1 1 1 1 0 1

PV 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 1

MetaFE AD 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0

AV 1–2 5 2 1–2 2 3 4 4 2 2 4–5 3 1–3 1 4 3–4 4

PV 1 0 1 1 0 1 1 1 0 1 0 1 1 1 1 0 1

MetaTI AD 0 0 0 0 0 0 0 0 0 0 0 0 0 0–1 1 0 1

AV 2 1 2 2 0 3 4 3 4 3 0 3 2–3 2 3 0 3

PV 0 0 0 0–1 0 1 2 2 0 1 0 0 0 0 1 0–1 1

MetaTA AV 1 0 1 1 0 1 1 1 2 1 0 1 1 1 1 0 1

PV 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 1



TABLE 5. Number of secondary setae1 on the legs of instar II of selected species of Rhantus Dejean (acronyms as inTable 1). A = anterior, AD = anterodorsal, AV = anteroventral, CO = coxa, D = dorsal, Di = distal, FE = femur, NS =natatory setae, PD = posterodorsal, Pr = proximal, PV = posteroventral, TA = tarsus, TI = tibia, TR = trochanter, V =ventral, n = number of specimens studied, Total = total number of secondary setae on segment.

Segment Sensillarseries

ANI(n = 2)

ANT(n = 2)

BIN(n = 2)

CAG(n = 3)

CAL(n = 2)

CON(n = 1) 2

EXS(n = 2)

FEN(n = 1) 2

FOR3

(n = 3)FRO(n = 1) 2

GRA(n = 2)

NOT(n = 1) 2

ProCO D 5–6 7–10 8 5–8 3–9 7 6 4–6 12 4–5 8–9 6–7

A 5–6 4–6 2–4 3–5 4–5 3–4 3 4–5 5–7 3–4 5 4–5

V 3–4 3 3 3–6 2–4 3–5 4–5 3 2–3 4–5 6–9 4–5

Total 14–15 15–19 13–15 13–17 10–17 14–15 13–14 11–14 19–22 12–13 20–22 15–16

ProTR Pr 1 1–3 1 0–1 0 0–1 1 1 1 0 3 0

Di 0 0 0 0–1 0 0 0 0–1 0 0 1 0

Total 1 1–3 1 0–1 0 0 1 1–2 1 0 4 0

ProFE NS (PD) 13– 15 27– 28 15– 18 15– 18 24– 33 17– 19 17 14– 17 13– 17 12– 17 10– 11 16– 17

AD 8 9–11 8–10 8–14 5–9 8–12 11–14 11–13 8–11 8 14–16 11–12

AV 7–8 7–9 9–10 7–10 8–11 10–13 14–15 20–22 12–13 5–6 19–25 13–14

PD 0 0 0 0 0 0 0 0 0 0 0–1 0

PV 4–6 6–7 6–8 6–8 4–6 6–8 8–9 11 8–9 6–7 13–14 9

Total 34–35 49–55 38–46 39–47 47–53 44–49 51–54 56–63 26–31 32–37 60–63 50–51

ProTI NS (PD) 14–15 22–23 15–16 15–18 27–33 21 15–17 13–18 15–18 15–17 10 14–16

AD 2–3 1 2 3–5 2–3 5–6 4–6 2–3 3–4 3 2–3 2–3

AV 4–5 3–4 4–6 3–4 10–12 6–8 7 7 4–6 5 9–11 6

PV 3–5 3–4 4 2–4 2 5–6 5 6–7 3–4 3–4 7–9 3–4

Total 25–26 29–32 26–27 26–27 41–50 39 31–35 30–33 26–31 27–32 28–33 26–28

ProTA NS (PD) 11–12 12–14 13–14 14–16 22–24 17–18 14–15 13–14 14–15 14 8–10 14–15

AD 2 0 2 2 2–3 2–3 2 2 2–3 2 1 1–2

AV 4–6 3–4 4–5 4–5 9–10 6–8 6 5 6 4–5 7–8 5–6

PV 0–1 3 0 0 0 3–4 3–4 5–7 2 1 6–7 3

Total 19 18–21 18–20 20–23 34–36 28–30 25–27 25–28 24–26 19–22 23–25 24–25

MesoCO D 5 8–10 6–8 4–6 5–7 5–6 4–5 5 8–10 5 7 5–8

A 3–4 4–7 2–4 4 3–4 3 3–4 3–4 4–5 3 7 2–4

V 4–5 3–5 3 3–7 3 3–4 4–5 4–5 2–4 6 7–12 5–6

Total 12–14 17–21 13 11–16 11–14 11–13 12–13 12–14 16–18 14 21–26 15

MesoTR Pr 1 2–3 1 0 0 0 1–2 1–2 1 0 5–7 0

Di 0 0–1 0 0–1 0 0 0 0 0 0 1–2 0

Total 1 2–3 1 0–1 0 0 1–2 1–2 1 0 6–9 0

MesoFE NS (PD) 12 23–25 13–14 14 21–29 15–16 12–15 15–18 14–17 11–13 8–9 14–15

AD 9–10 11–12 10–13 10–15 8–9 9–11 10–16 15 12–13 7–9 16–17 13–14

AV 9 10–12 11–12 9–13 13 17–20 17–18 17 11–12 6–9 18–19 12–13

PV 7 8–10 6–7 6–10 6–8 6–7 7–8 10 8–10 7–8 13–16 8–9

Total 37–38 52–59 41–45 42–47 48–59 41–49 48–55 57–60 45–52 34–36 56–60 48–50

MesoTI NS (PD) 13–17 26–28 16–17 17–20 31–36 19–22 18–19 18–19 15–20 18 11–14 16–18

AD 3–5 3–4 4 6–8 6 5–6 6 5 5 5 5 4

AV 7–8 5–8 8–9 4–9 11–12 11–14 9–11 10–11 8–9 8–9 11–12 7–9

PV 5–6 4–5 4 3–7 3–4 5–8 4–6 6–7 3 3 7–8 4

Total 29–35 38–45 32–34 34–39 52–57 41–49 39–40 40–41 31–37 34–35 34–39 33

continued next page



1 including additional setae, cf. material and methods; 2 both legs included; 3 Alarie & Wang (2004).

lateroventral process of A3 not protruding. Mandible (Fig. 9). Prominent, falciform, wide at base, sharpapically, 2.11–3.00 times as long as broad, 0.52–0.72 times as long as HL; mandibular channel present,pubescence developed along inner margins. Maxilla (Figs 5–6, 102, 192–193). Cardo small, narrow; stipeswell developed, subtrapezoidal, either without or with a few microspinulae along inner margin; palpifer short,broad, palpomere-like, 0.20–0.44 times as long as MP1; palpus 3-segmented (A/MP = 1.27–1.76), MP1 theshortest, MP3 the longest and narrowest (MP3/MP2 = 1.05–1.60); galea well developed, subconical (GA/MP1 = 0.43–1.28). Labium (Figs 7–8, 194–195). Prementum subrectangular, broader than long, anteriormargin straight to shallowly emarginate, with microspinulae on dorsal surface; palpus 2-segmented, elongate,slender (MP/LP = 0.94–1.25); palpomeres subequal in length or LP2 somewhat longer than LP1 (LP2/LP1 =0.85–1.34). Thorax. Terga convex, lateral margins curved; pronotum about as long as meso- and metanotumcombined, meso- and metanotum subequal; sagittal line visible; tergites subrectangular, transversal, marginsrounded, protergite more developed than the others, meso- and metatergite with anterotransverse carina;venter membranous; spiracular openings absent. Legs (Figs 10–11, 21–22, 31–32, 41–42, 52–53, 67–68, 77–78, 87–88, 103–104, 118–119, 128–129, 138–139, 148–149, 163–164, 178–179, 188–189, 202–203). Long,



ANI(n = 2)

ANT(n = 2)

BIN(n = 2)

CAG(n = 3)

CAL(n = 2)

CON(n = 1) 2

EXS(n = 2)

FEN(n = 1) 2

FOR3

(n = 3)FRO(n = 1) 2

GRA(n = 2)

NOT(n = 1) 2

MesoTA NS (PD) 15–16 19 15–16 16–21 22–31 20 15–20 16–19 15–18 17–20 14–15 17

AD 2 1 2–7 2–3 2–3 4 3–4 2 3–4 2 1 2–3

AV 6–7 5–7 6–8 5–7 11–13 9–11 9–11 6–8 6–8 6–7 9–10 7

PV 3–4 3–5 2 1–3 0 5 5 6–8 3 3 7–8 4

Total 27–28 28–32 27–31 25–33 35–47 38–40 33–39 30–37 28–31 28–32 32–33 30–31

MetaCO D 3 5–7 5–6 3–5 3 4–5 3–4 6 5–7 3 5 5–6

A 2–3 4–7 2–3 3–5 2–4 4 5 5 3–5 4 7 2–4

V 3–6 3–5 3 4–6 2–3 2–3 4–5 3–4 5–6 5–6 7–11 6–7

Total 9–11 15–19 11 12–16 7–10 10 13 14–15 15–17 12–13 19–23 14–16

MetaTR Pr 1 1–6 1 0–1 0–1 0 2 1–2 1–2 0 5 1

Di 0 1–2 0 0–1 0 0 0 0 0 0 1–2 0–1

Total 1 3–7 1 0–1 0–1 0 2 1–2 1–2 0 6–7 1–2

MetaFE NS (PD) 5 8–9 5–6 1–4 8–10 6–8 3–5 4–5 6–8 6 3–4 5–7

AD 9–11 13–16 11 10–16 9–10 12–15 13–17 11–14 12–13 9–10 21–24 14–13

AV 8–9 9–11 10 6–10 7–10 12–15 11–14 9–16 11–13 7–8 17–19 11–16

PV 7 8–13 5–6 6–8 5–6 4–6 5–6 9–10 7 7 13 7

Total 29–32 38–49 31–33 23–33 29–36 39 35–39 36–42 36–41 30 55–59 38–42

MetaTI NS (PD) 15–17 24–26 19–20 19–20 25–32 18–20 20 18 15–17 20–21 11–12 16–18

AD 5–7 5 5 5–10 5–6 7–8 8–9 7 6 7–8 9–10 6–7

AV 9–10 8 10–11 7–10 9–11 11–14 8–12 9 7–8 9–10 11 8–10

PV 3–5 4–5 2–3 3–6 3 5 5 5 3–4 3–4 7–8 4

Total 33–38 41–44 36–39 39–43 42–52 42–45 41–46 39 32–35 41 38–41 34–39

MetaTA NS (PD) 16–18 23–24 17–18 18–23 25–32 24 21 22 17 19–21 15–16 19–20

AD 2–3 1–3 2–4 3–4 5–6 3 4 4 3–5 4 4 3

AV 6–7 6–8 8–9 7–9 9–11 10–11 11–13 9 6–8 8–9 10–11 9

PV 4–5 4–6 2 2–3 3 4 4 5 1–3 2–3 7–9 3–4

Total 29–32 34–41 29–32 32–35 42–52 41–42 40–42 40 27–32 35 38 35



6-segmented (sensu Lawrence 1991); L3 the longest, L1 the shortest; L3 = 2.38–4.16 mm; L3/HW = 2.54–3.43; CO robust, elongate, TR subdivided into 2 parts, FE, TI and TA slender, subcylindrical; two long,slender, slightly curved claws, posterior claw shorter than anterior one on L1 and L2, anterior claw eithershorter than or subequal to posterior one on L3; claws with basoventral spinulae; legs covered withmicrospinulae more or less developed; FE, TI and TA with a row of ventral spinulae variably developed.

Abdomen. 8-segmented; segments I–VII sclerotized dorsally, membranous ventrally, progressivelynarrowing to apex; sagittal line visible on segments I–III or I–IV; tergites I–VI similar to each other, narrow,transverse, laterally rounded, with anterotransverse carina; segment VII somewhat longer, withanterotransverse carina; spiracular openings absent on segments I–VII; LAS (Figs 12–13, 23, 33, 43, 54, 69,79, 89, 105, 120, 130, 140, 150, 165, 180, 190, 204) variable in size, short to very elongate, completelysclerotized, ring-like, without anterotransverse carina (LAS = 0.51–1.00 mm, LAS/HW = 0.58–0.99), coveredwith densely distributed microspinulae; siphon reduced. Urogomphus (Figs 14, 24, 34, 44, 55, 70, 80, 90, 106,121, 131, 141, 151, 166, 181, 191, 205). One-segmented, variable in length (U = 0.84–1.83 mm, U/LAS =0.87–3.12, U/HW = 0.80–1.87), with microspinulae either on whole surface or only at about basal 1/2.

Chaetotaxy. First-instar larvae of Rhantus present the following characteristics and differences with thegeneralized Colymbetinae larva (Alarie 1995, 1998; Alarie & Hughes 2006): FR with 15–35 more or lessdeveloped setae on anterior margin, arranged in a single row, pore FRe either present (Figs 20, 30, 51, 66, 76,86, 101, 117, 137, 147, 162, 177, 201) or absent (Figs 1, 40, 127, 187), seta FR8 elongate (Figs 1, 20, 30, 40,51, 66, 76, 86, 101, 117, 127, 137, 147, 162, 177, 187, 201); two additional pores on ventral surface of A3(Fig. 4); seta MN1 inserted either more or less distally (Fig. 9); pore MXa absent (Figs 5–6); spine-like setaeon anterodorsal surface of prementum either very short (Fig. 7) or elongate (Fig. 194), prementum with avariable number of additional spine-like setae on anterodorsal surface (Figs 7, 194), LP2 with 1–2 minutestructures near setae LA10 and LA12; presence of a variable number of additional setae on legs (Table 4);setae FE6 and TI6 elongate and setiform (Figs 11, 22, 32, 42, 53, 68, 78, 88, 104, 119, 129, 139, 149, 164,179, 189, 203); seta FE5 on meso- and metafemur either moderately elongate and spiniform (Figs 11, 42, 129,189) or very elongate and setiform (Figs 22, 32, 53, 68, 78, 88, 104, 119, 139, 149, 164, 179, 203); seta TI7either short and spiniform (Figs 11, 42, 129) or elongate and setiform (Figs 22, 32, 53, 68, 78, 88, 104, 119,139, 149, 164, 179, 189, 203); U with one additional, minute, apical seta, and either without (Figs 14, 24, 34,44, 55, 70, 80, 90, 106, 121, 131, 141, 151, 166, 181, 205) or with (Fig. 191) numerous additional long setae;primary seta UR4 either shorter than any of setae UR5, UR6, or UR8 (Figs 24, 34, 44, 55, 141, 151, 166) orelongate, subequal in length to any of setae UR5, UR6, or UR8 (Figs 14, 70, 80, 90, 106, 121, 131, 181, 205);seta UR5 either articulated posteriorly (Figs 14, 24, 34, 55, 70, 80, 90, 106, 121, 131, 141, 151, 166, 181, 205)or anteriorly (Fig. 44) to seta UR7.

Second-instar larvaAs first instar except as follows:Colour. Some species predominantly yellowish, others light brown to brown or almost black; head,

thoracic and abdominal tergites either without or with colour pattern, remaining parts without colour pattern.Head. HL = 1.32–2.28 mm; HW = 1.25–2.20 mm; FRL = 0.60–1.02 mm. Head capsule. Subquadrate,

parallel sided (HL/HW = 0.88–1.16, HW/OCW = 1.47–2.11); COL/HL = 0.54–0.59; FR/HL 0.33–0.48; eggbursters lacking. Antenna. Shorter to slightly longer than HW (A/HW = 0.55–1.12); A1 the shortest,remaining segments subequal or A2 and A3 the longest (A4/A3 = 0.70–1.20). Mandible. 2.42–3.09 times aslong as broad, 0.45–0.65 times as long as HL. Maxilla. PPF/MP1 = 0.25–0.45, A/MP = 1.29–1.85; either MP2or MP3 the longest (MP3/MP2 = 0.78–1.41); GA/MP1 = 0.29–0.95. Labium. MP/LP = 0.96–1.43; LP1 eitherlonger or somewhat shorter than LP2 (LP2/LP1 = 0.79–1.10). Thorax. Legs. L3 = 3.85–6.06 mm, L3/HW = 2.55–3.17; all legs without microspinulae, or L2 and L3with microspinulae on dorsal surface of CO.



TABLE 6. Number of secondary setae1 on the legs of instar II of selected species of Rhantus Dejean (acronyms as inTable 1). A = anterior, AD = anterodorsal, AV = anteroventral, CO = coxa, D = dorsal, Di = distal, FE = femur, NS =natatory setae, PD = posterodorsal, PV = posteroventral, Pr = proximal, TA = tarsus, TI = tibia, TR = trochanter, V =ventral, n = number of specimens studied, Total = total number of secondary setae on segment.


ORB(n = 3)

PHO(n = 2)

SIG(n = 3)

SOC(n = 2)

SUT(n = 2)

VAL(n = 1) 2

WAL(n = 2)

ProCO D 5–6 5–6 3–6 7 8–9 11–13 6–7

A 4 2 2–4 5–7 2–4 5 4

V 0–1 3–4 2–6 6–7 3–5 2–3 4

Total 9–10 11 8–10 18–21 15–16 19–20 14–15

ProTR Pr 0–1 0 0 0 0 2 0

Di 0 0–1 0 0 0 0 0

Total 0–1 0–1 0 0 0 2 0

ProFE NS (PD) 10–17 13–19 11–13 18–19 14–15 14–15 18

AD 8–11 11 6–9 7–9 12–13 13–15 10–11

AV 8–12 10–14 6–8 9–10 10–12 14–16 14

PV 6–8 8 4–7 8–9 8 9–10 8

Total 33–45 46–48 27–30 43–46 45–47 52–54 50–51

ProTI NS (PD) 8–15 17–18 10–13 14–18 15–16 12 18

AD 1 2–3 3 2–4 3–5 5–6 3–4

AV 2–4 5–7 2–4 4–5 5 4–6 4–6

PV 2–3 3–5 2–4 3 4–5 8–9 4

Total 13–22 29–31 18–21 24–29 28–30 30–32 30–31

ProTA NS (PD) 7–9 15–16 9–11 13 13–15 12–13 16

AD 0 2–3 2 2 2 3–5 2

AV 2–4 6 3–4 5 6 4–5 5

PV 0 0 0 0 4 5–6 3

Total 9–12 24 15–17 20 25–27 26–27 26

MesoCO D 6–7 5–6 3–4 7–8 5–7 9–11 5–6

A 4–5 2–3 2–3 3–4 3–4 4–7 3–4

V 1–4 3–5 2–4 4–7 5–7 4–7 3–4

Total 11–14 12 8–10 15–18 15–16 20–22 12–13

MesoTR Pr 1 0–2 0 0 1 4–5 0

Di 0 0 0 0 0–1 0–1 0

Total 1 0–2 0 0 1–2 5 0

MesoFE NS (PD) 9–14 13–15 7–9 15–17 11–12 13–14 12–16

AD 7–14 12–13 6–9 11–13 10–11 17 7–12

AV 11–14 9–14 7–12 7–9 13–14 13–17 12

PV 7–9 9 4–6 9–10 7–8 8–9 8

Total 40–46 46–48 26–34 45–46 42–44 53–55 39–48

MesoTI NS (PD) 12–16 18–19 12–14 18–19 16–17 13 17

AD 2–3 5 3–5 5–6 5–6 9 4–5

AV 4–6 9–11 6–7 7 7–8 7–10 8–9

PV 3 5 2–4 4 4–6 8 4

Total 23–26 38–39 26–28 35 33–36 37–40 33–35

continued next page



1 including additional setae, cf. material and methods; 2 both legs included.

Abdomen. Sagittal line visible on segments I–VI; segment VII completely sclerotized, ring-like, withanterotransverse carina dorsally and laterally; LAS with anterotransverse carina (LAS = 1.03–2.18 mm, LAS/HW = 0.66–1.37). Urogomphus. Fractured proximally (as in Figs 19, 29, 39, 60, 65, 85, 95, 100, 126, 136,146, 156, 161, 171, 176, 186, 210) or not (as in Figs 50, 75, 111, 116, 195); U = 0.91–2.70 mm, U/LAS =0.44–2.39, U/HW = 0.57–1.69; either without microspinulae or with microspinulae basally.

Chaetotaxy. Head capsule with several secondary pores and hair-like setae; FR with 32–88 lamellaeclypeales along apical margin, arranged in a double row; PA with 3–13 temporal spine-like setae posterior tostemmata; MN with several minute secondary setae on dorsal, ventral and external margins; number andposition of leg secondary setae represented in Tables 5–6; natatory setae on posterodorsal margin of FE, TIand TA (on metafemur restricted to distal 1/3 to 2/3) (as in Figs 17, 27, 37, 48, 58; 63, 73, 83, 93, 98, 109, 114,124, 134, 144, 154, 159, 169, 174, 184, 198, 208); LAS with several hair-like and/or spine-like secondarysetae (except medially on ventral surface) (as in Figs 18, 28, 38, 49, 59, 64, 74, 84, 94, 99, 110, 115, 125, 135,145, 155, 160, 170, 175, 185, 199, 209); U either without secondary setation (as in Figs 19, 50, 136), or withnumerous spine-like and/or hair-like secondary setae (as in Figs 29, 39, 60, 65, 75, 85, 95, 100, 111, 116, 126,146, 156, 161, 171, 176, 186, 200, 210).



ORB(n = 3)

PHO(n = 2)

SIG(n = 3)

SOC(n = 2)

SUT(n = 2)

VAL(n = 1) 2

WAL(n = 2)

MesoTA NS (PD) 11–12 17–19 14 18–19 16–17 16–17 17–20

AD 0–1 3–4 2–3 3 2 7 2

AV 5–6 8–9 5–8 6–8 7–8 8–9 6–8

PV 0 2 0–2 3 4 7–8 5

Total 16–18 32 21–27 31–32 29–31 38–41 32–33

MetaCO D 3–5 3–5 2–3 4–5 4–6 5–6 4–5

A 2–4 1–3 0–2 3–5 2–3 6 4

V 1–4 3–6 2–4 5–6 2 5 4

Total 7–14 9–12 5–8 13–15 9–10 16–17 12–13

MetaTR Pr 1 0–1 0 0 0–1 4 0–1

Di 0–1 0 0 0 0 0 0

Total 1–2 0–1 0 0 0–1 4 0

MetaFE NS (PD) 2–6 5–8 1–2 9–10 4 3–4 7

AD 10–14 14–15 7–10 13 14–15 17–21 13–15

AV 11–13 10–13 6–8 8–9 11 14–15 9–10

PV 7–10 9–13 4–7 8–9 6 9 6–7

Total 32–40 42–45 20–21 39–40 35–36 43–44 37

MetaTI NS (PD) 14–16 18–23 13–15 20 16–17 14–15 17–19

AD 3–5 6–10 4–6 9 6 12 5–6

AV 6–8 9–10 6–8 6–8 8–6 7–10 8–9

PV 0–2 6–8 1–3 4–5 3–6 9 3

Total 27–30 41–49 24–29 40–41 33–39 43–45 34–36

MetaTA NS (PD) 15–19 22–24 16–18 21–22 17–19 20–21 22–24

AD 1–2 4–5 2–3 4 2 9 4

AV 6–8 11–12 6–9 8 8 10 8–9

PV 0 3 1–2 3–4 2–4 8–9 3–4

Total 23–27 41–43 26–30 37 31 47–49 37–47



TABLE 7. Number of secondary setae1 on the legs of instar III of selected species of Rhantus Dejean (acronyms as inTable 1). A = anterior, AD = anterodorsal, AV = anteroventral, CO = coxa, D = dorsal, Di = distal, FE = femur, NS =natatory setae, PD = posterodorsal, PV = posteroventral, Pr = proximal, TA = tarsus, TI = tibia, TR = trochanter, V =ventral, n = number of specimens studied, ns = non–available, Total = total number of secondary setae on segment.


ANI(n= 3)

ANT(n= 3)

BIN(n = 3)

CAG(n= 3)

CAL(n = 3)

CAP(n = 1) 2

CON(n = 1) 2

EXS(n = 2)

FEN(n = 2)

FOR3

(n = 6)FRO(n = 1) 2

GRA(n = 2)

ProCO D 8–11 17–20 10–13 11–18 12–22 14–15 12–13 10–12 15–18 15–19 13–15 14–16

A 6–8 17–20 7–9 6–11 5–6 8 5–6 7–10 11–18 4–9 9–10 7–10

V 3–4 4–5 2–3 4–7 3–4 6 5 4–5 5 3–4 4–5 7

Total 18–22 41–43 21–22 22–30 21–31 28–29 22–24 21–27 31–41 24–27 27–29 28–33

ProTR Pr 2–4 4–7 2–4 2–4 1 2–3 3–4 2–4 4–6 1–2 2–3 4–5

Di 0 0–1 0 0 0 0 0 0 0 0 0 1–2

Total 2–4 4–7 2–4 2–4 1 2–3 3–4 2–4 4–6 1–2 2–3 5–7

ProFE NS (PD) 29–37 59–60 25–30 34–39 56–62 29 38–42 27–31 33–36 26–28 33–35 15–17

AD 8–12 9–12 10–13 14–18 6–8 11–13 11–12 12–14 13 11–13 9–12 17

AV 17–21 8–10 13–18 14–18 13–15 20–21 21–22 18–24 31–33 18–19 17–19 23–24

PD 0 0 0 0 0 0 0 0–1 0 0 0 0

PV 8–11 7–10 12–14 7–11 6–8 7–10 13–15 10–13 15–17 7–11 9–11 17–18

Total 62–81 83–92 62–75 70–83 81–92 67–73 85–89 67–83 95–96 64–69 72–73 73–75

ProTI NS (PD) 27–35 39 24–25 30–33 52–63 26–27 33–34 24–28 27–29 25–26 28–30 12–16

AD 2–3 1 2–3 3–5 6–8 3 5–6 2–3 3 2–4 3 2–4

AV 5–7 3–5 3–5 2–5 10–12 6–7 8–9 5 6–7 5 6 11–12

PV 3–5 3–4 3–4 2–4 3–4 4 6 5–7 7 4 5 7–8

Total 38–47 46–49 34–35 40–44 67–81 40 50–55 36–43 43–46 37–41 42–44 36

ProTA NS (PD) 19–23 20–22 18–20 24–27 44–50 19–20 26–31 19–23 21 21–24 22–23 9–12

AD 2 0 2 2–3 2 2 3 2 1–2 2–3 1–2 1

AV 5–6 3–4 5 4–6 10–12 5 7–9 5–6 4–7 5–6 5 6–8

PV 0–1 3–4 0 0 0 0 3–4 2–4 6–7 1–2 1–2 7–8

Total 27–31 26–30 25–26 24–27 56–64 26–27 41–45 28–35 33–36 31–32 30–31 24–28

MesoCO D 8–10 17–24 12–19 13–16 13–20 14–15 14 7–9 13–17 12–14 13–16 12–13

A 5–8 18–25 8–9 4–10 5–8 7–10 5–8 8–11 12–18 7–14 10 10–13

V 4 3–7 3–5 5–10 2–6 6 4–5 4–6 5–6 4–7 5–6 6–10

Total 18–20 43–51 25–31 24–32 20–31 27–31 24–26 19–26 34–37 28–31 29–31 28–36

MesoTR Pr 4–5 4–7 4–7 3–4 1 2–3 3–5 3–4 5–7 2–3 2–3 8–9

Di 0 0–1 0 0–1 0 0 0 0 0 0 0 1–3

Total 4–5 4–7 4–7 3–5 1 2–3 0 3–4 5–7 2–3 2–3 9–10

MesoFE NS (PD) 26–33 52–59 25–30 32–35 50–65 28–29 33–34 20–27 28–32 23–24 24–28 13

AD 10–12 12–14 14–19 15–19 7–9 14–15 13–16 14–17 13–15 12–14 13 18

AV 15–19 10–12 15–19 11–15 10–14 16–18 26–29 17–24 24–26 12–14 19–21 19–23

PD 0 0 0 0 0 0 0–1 0 0 0 0 0

PV 11–16 9–12 14–18 11–14 7 13–16 16–19 11–14 6–7 11–12 15 15–17

Total 63–80 83–97 68–86 70–81 74–93 73–76 92–95 68–82 84–93 60–61 73–75 65–71

MesoTI NS (PD) 30–35 44–50 27–33 37–44 64–71 32–35 39–42 32 31–34 27–31 30–32 16–18

AD 4–5 3–4 5–6 6–8 3–5 6–7 7 4–7 5 6 6–7 4

AV 7–11 7–8 8–9 6–8 14–17 9 16 10–12 9–11 6–9 10 11–12

PV 4–5 4–6 4–7 2–4 4 5–6 7–9 6 6–7 3–5 5 8–9

Total 46–55 58–68 45–53 55–65 85–97 53–56 69–74 54–55 54 43–50 51–54 40–42

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1 Including additional setae, cf. material and methods; 2 both legs included; 3 Alarie & Wang (2004).

Third-instar larva (Figs 15–19, 25–29, 35–39, 45–50, 56–65, 71–75, 81–85, 91–100, 107–116, 122–126, 132–136, 142–146,152–161, 167–171, 172–176, 181–186, 196–201, 206–210).

As second-instar larva except as follows:Colour. Some species predominantly yellowish to light brown, others reddish to dark yellow or light

brown to brown.Head (Figs 15, 25, 35, 45, 56, 61, 71, 81, 91, 96, 107, 112, 122, 132, 142, 152, 157, 167, 172, 182, 196,

206). HL = 2.10–3.75 mm; HW = 1.85–4.28 mm; FRL = 0.85–1.44 mm. Either as long or longer than broad(HL/HW = 0.88–1.30), sides either subparallel with maximum width at stemmata, or slightly converginganteriorly with maximum width posterior to stemmata; HW/OCW = 1.41–2.25; ecdysial line clearly visible ordifficult to see in darker species (COL/HL = 0.50–0.65); FR/HL = 0.35–0.48; microspinulae reduced tolacking. Antenna. A2, A3 and A4 fractured proximally (Fig. 46) or not; A/HW = 0.50–0.93; either A3 or A4the shortest (A4/A3 = 0.63–1.20). Mandible. 2.42–3.43 times as long as broad, 0.44–0.62 times as long as HL.Maxilla. MP2 and MP3 fractured proximally or not; PPF/MP1 = 0.24–0.43, A/MP = 1.24–1.74; MP1 and



ANI(n= 3)

ANT(n= 3)

BIN(n = 3)

CAG(n= 3)

CAL(n = 3)

CAP(n = 1) 2

CON(n = 1) 2

EXS(n = 2)

FEN(n = 2)

FOR3

(n = 6)FRO(n = 1) 2

GRA(n = 2)

MesoTA NS (PD) 26–29 30–31 25–27 33–41 53–56 28–30 34–38 28–31 27–31 26–29 29–30 17–19

AD 2 0–1 2–3 2–3 2–4 2–3 3–4 2–3 2 3 2 2

AV 7–8 6–7 8–9 7–9 12–15 7–8 11 9–11 7–8 7–8 7–8 7

PV 2–4 4–5 1–2 2–4 0 2–4 6 4 6–7 2–3 2–3 7

Total 38–42 40–44 37–39 46–57 68–74 39–45 53–59 43–49 43–47 39–42 41–42 33–36

MetaCO D 7–9 17–24 12–13 10–13 8–10 9–13 11–12 8–10 15–21 10–13 10–12 11–13

A 4–7 21–26 9–15 6–8 5–8 8–9 9–10 7–11 13–18 7–9 10–13 12–14

V 2–5 3–7 2–5 4–10 1–7 7–8 3–4 3–4 4 5–6 3–5 7–10

Total 13–19 45–49 24–33 20–29 14–24 25–29 23–26 18–25 32–43 23–27 26–27 32–35

MetaTR Pr 3–5 4–6 3–5 3–5 1–2 2–4 3–4 5–6 6–8 2–3 3–4 8

Di 1 1–2 0 0–1 0 0 0 0–1 0 0 0–1 2–4

Total 3–5 4–6 3–5 3–5 1–2 2–4 3–4 5–7 6–8 2–3 4 10–12

MetaFE NS (PD) 7–13 24–25 10–15 11–16 29–34 14 13–15 7–8 7–14 12–13 11–12 2–4

AD 12–15 13–16 13–18 16–23 6–7 16–17 16–19 14–17 17–18 15–18 16–17 20–22

AV 13–18 11–13 13–18 10–15 9–15 15–18 20–28 18–22 16–24 12–13 19–21 17

PV 10–16 9–12 15–19 11–15 6–9 14 15 12–15 14–18 10–13 14 18–21

Total 45–62 57–66 51–69 54–65 51–62 60–62 69–72 54–59 56–58 49–59 62 59–62

MetaTI NS (PD) 29–36 48 29–32 41–43 55–66 32–36 39–41 30–31 32 27–28 28–31 17

AD 7 4–6 7–9 10–11 4–7 8–9 10–14 7–9 8–9 8–10 9–10 7

AV 5–7 9–12 8–10 7–12 11–16 10–11 17–18 10–11 10 8–9 9–10 11

PV 4–6 4–7 4–6 4–6 2–5 4–5 6–7 6 6–7 3–4 4 10

Total 48–61 65–73 50–55 54–59 74–81 54–61 73–79 55 56–58 48–49 52–53 45

MetaTA NS (PD) 29–34 38–39 26–29 41–42 42–55 34–37 41–42 33–35 34–35 30–31 28–30 21–24

AD 2–4 2 2–3 2–6 2–3 4 3 3 3 4–5 3–4 4

AV 8 8–10 10 7–11 11–13 9–10 11–13 9–11 10 9 10–11 10–12

PV 1–5 4–6 2–3 2–6 0 3 6 4–5 5–6 2–3 1–3 8–10

Total 41–51 52–57 42–44 54–59 56–71 51–53 62–63 51–52 52–54 46–47 43–47 43–50



MP2 subequal in length, MP3 slightly shorter or longer (MP3/MP2 = 0.69–1.21); GA/MP1 = 0.32–0.81.Labium. LP2 fractured proximally or not; MP/LP = 0.99–1.43; LP1 longer than LP2 (LP2/LP1 = 0.62–0.87).

Thorax. Protergite subquadrate, strongly convex but turning to concave on laterals; spiracular openingspresent on mesothorax. Legs (Figs 16–17, 26–27, 36–37, 47–48, 57–58, 62–63, 72–73, 82–83, 92–93, 97–98,108–109, 113–114, 123–124, 133–134, 143–144, 153–154, 158–159, 168–169, 173–174, 183–184, 197–198,207–208). L3 = 5.42–10.01 mm, L3/HW = 2.24–2.94; legs without microspinulae or with microspinulae ondorsal surface of CO.

Abdomen. Sagittal line visible on segments I–VI or I–VII; segment VII with anterotransverse carina;spiracular openings present on segments I–VII; LAS (Figs 18, 28, 38, 49, 59, 64, 74, 84, 94, 99, 110, 115, 125,135, 145, 155, 160, 170, 175, 185, 199, 209) = 1.33–3.68 mm, LAS/HW = 0.62–1.53. Urogomphus (Figs 19,29, 39, 50, 60, 65, 75, 85, 95, 100, 111, 116, 126, 136, 146, 156, 161, 171, 176, 186, 200, 210). U = 0.85–3.70mm, U/LAS = 0.24–2.23, U/HW = 0.35–1.51.

Chaetotaxy. FR with 60–90 spatulate setae on apical margin; PA with 6–16 temporal spine-like setaeposterior to stemmata; position and number of leg secondary setae as represented in Tables 7–8; U eitherwithout secondary setation (Figs 19, 50, 136) or with numerous spine-like and/or hair-like secondary setae(Figs 29, 39, 60, 65, 75, 85, 95, 100, 111, 116, 126, 146, 156, 161, 171, 176, 186, 200, 210).

Key to species of instar I and III of the genus Rhantus

In addition to the species described in this paper, this key of identification includes R. formosanus, R.monteithi and R. poellerbauerae, which were described recently with much details, including chaetotaxy(Alarie & Wang 2004; Balke et al. 2007).

1. Frontoclypeus with two egg bursters (cf., Fig. 1); legs lacking natatory setae; spiracles lacking (instar I) ................ 2- Frontoclypeus smooth, lacking egg bursters; legs with natatory setae along dorsal margin of femora, tibiae and tarsi

(cf., Fig. 17); spiracles lacking (instar II) or present (instar III) ............................................................................... 182. Adnasaliae diverging outward (Fig. 101); galea elongate, longer than length of maxillary palpomere I (Fig. 102);

cranium not constricted at level of occiput (Fig. 101); primary setae MX5 and MX7 longer than length of galea (Fig.102); femora with at least 1 dorsal additional seta (Fig. 103); primary seta UR2 longer than seta UR3 (Fig. 106);antennomere III lacking a ventroapical spinula; antennomere IV > 1.50 times as long as antennomere III; maxillarypalpomere III > 1.60 times as long as maxillary palpomere II; urogomphi subequal in length to length of lastabdominal segment; occipital carina lightly impressed (Fig. 101) ..................................................................R. grapii

- Adnasaliae converging inward (e.g., Fig. 1); galea shorter, less than 0.70 times as long as length of maxillarypalpomere I (Figs 5–6); cranium at least slightly constricted at level of occiput (e.g., Fig. 1); primary setae MX5 andMX7 shorter than length of galea (Fig. 6); femora lacking dorsal additional seta (e.g., Figs 10–11); primary seta UR2subequal in length to seta UR3 (e.g., Fig. 14); antennomere III with a ventroapical spinula (Fig. 4); antennomere IV< 1.30 times as long as antennomere III; maxillary palpomere III < 1.50 times as long as maxillary palpomere II;urogomphi subequal or distinctly longer than length of last abdominal segment; occipital carina well defined (e.g.,Fig. 1) ............................................................................................................................................................................ 3

3. Meso- and metafemoral primary seta FE5 short and spine-like (Figs 11, 42, 129, 189); protibia and each tarsuslacking additional setae; metafemur lacking posteroventral additional setae (Figs 11, 42, 129, 189); primary poreFRe absent (Figs 1, 40, 127, 187) ................................................................................................................................ 4

- Meso- and metafemoral primary seta FE5 elongate and hair-like (e.g., Fig. 22); protibia and each tarsus with at leastone additional seta (e.g., Fig. 21); metafemur with at least 1 posteroventral additional seta (e.g., Fig. 22); primarypore FRe present (e.g., Fig. 20).................................................................................................................................... 7

4. Urogomphus with several additional setae (Fig. 191); anterodorsal marginal primary setae of prementum elongate(Fig. 194); primary seta TI7 elongate and hair-like (Fig. 189); microspinulae present over most of dorsal surface of parietale; primary seta MX5 elongate, longer than length of palpifer (Fig. 192); microspinulae present over mostsurface of urogomphi ..................................................................................................................................... R. validus

- Urogomphus at most with one additional seta (e.g., Fig. 14); anterodorsal marginal primary setae of prementumminute (Fig. 7); primary seta TI7 short and spine-like (Figs 11, 42, 129); microspinulae present at most over



posterior 2/3 of dorsal surface of parietale; primary seta MX5 short, shorter than length of palpifer (Fig. 5);microspinulae restricted to basal 1/2 of urogomphi .................................................................................................... 5

5. Urogomphus slightly shorter than length of last abdominal segment; frontoclypeus extending mesally at about levelof tip of adnasaliae, with less than 14 lamellae clypeales (Fig. 40); stipes with one additional seta along innermargin; microspinulae over posterior 2/3 of dorsal surface of parietale; antennomere III lacking additionalventroapical pores; primary seta UR5 articulated anteriorly to seta UR7 (Fig. 44); femora with less than 2anteroventral additional setae (Fig. 41); metathoracic legs < 2.60 times HW; smaller species, HL < 0.90 mm .................................................................................................................................................................................... R. calidus

- Urogomphus longer, > 1.30 times length of last abdominal segment; frontoclypeus extending mesally well beyondadnasaliae, with more than 15 lamellae clypeales (Figs 1, 127); stipes lacking additional seta along inner margin;microspinulae at most over posterior 1/2 of dorsal surface of parietale; antennomere III with additional ventroapicalpores (Fig. 4): primary seta UR5 articulated posterior to seta UR7 (Figs 14, 131); femora with 4 or moreanteroventral additional setae (Figs 10, 128); metathoracic legs > 2.90 times HW; larger species, HL > 1.10 mm... 6

6. HW/OCW < 1.80; antenna < 0.70 times as long as HW; mesotibia with at least one additional seta; primary seta UR7slightly shorter than any of setae UR5, UR6, UR8 (Fig. 14); frontoclypeus with more than 27 lamellae clypeales;tarsal microspinulae over basal 2/3 to 3/4 ...................................................................................R. antarcticus nahueli

- HW/OCW > 2.00; antenna > 0.80 times as long as HW; mesotibia lacking additional setae; primary seta UR7 about1/2 as long as any of setae UR5, UR6, UR8 (Fig. 131); frontoclypeus with less than 16 lamellae clypeales; tarsalmicrospinulae more reduced, covering at most basal 1/2 ............................................................................. R. orbignyi

7. Antennae, maxillary and labial palpomeres densely covered with microspinulae ...................................................... 8 - Antennae, maxillary and labial palpomeres smooth, lacking microspinulae............................................................... 9 8. Microspinulae lacking over dorsal surface of frontoclypeus; microspinulae present over posterior 2/3 of dorsal

surface of parietale; procoxal seta CO7 articulated distally to articulation of seta CO6; labial palpomere II > 1.10times as long as labial palpomere I; frontoclypeus with more than 24 lamellae clypeales ...................R. anisonychus

- Microspinulae present over most of dorsal surface of frontoclypeus and parietale; procoxal seta CO7 articulatedproximally to articulation of seta CO6; labial palpomere II < 1.00 times as long as labial palpomere I; frontoclypeuswith less than 20 lamellae clypeales ........................................................................................................... R. binotatus

9. Microspinulae present over most of dorsal surface of parietale ................................................................................ 10- Microspinulae present at most over posterior 1/2 of dorsal surface of parietale ........................................................ 1310. Microspinulae present at most over proximal 1/2 of urogomphi; primary seta UR4 as long or longer than any of setae

UR5, UR6, UR8 (Fig. 121); last abdominal segment longer, about 0.90 times as long as HW; urogomphi about 1.70times as long as last abdominal segment; Palearctic ............................................................................... R. notaticollis

- Microspinulae present over entire surface of urogomphi; primary seta UR4 distinctly shorter than any of setae UR5,UR6, UR8 (Figs 55, 141, 166); last abdominal segment shorter, < 0.70 times as long as HW; urogomphi > 2.30 timesas long as last abdominal segment: Afrotropical, Neotropical ................................................................................... 11

11. Lamellae clypeales spatulate; procoxal seta CO7 articulated proximally to articulation of seta CO6 ........ R. socialis- Lamellae clypeales spiniform or digitiform; procoxal seta CO7 articulated distally to articulation of seta CO6 ..... 1212. Tarsal claws with marginal spinulae over basal 2/3 to 3/4; Afrotropical............................................. R. phocaenarum- Tarsal claws with marginal spinulae restricted to basal 1/2 or less; Neotropical ...................................... R. calileguai13 Pro- and mesotibiae with at least one dorsal additional seta, with microspinulae over most of anterior surface; tarsal

claws with marginal spinulae over basal 2/3 to 3/4; Nearctic..................................................................................... 14- Pro- and mesotibiae lacking dorsal additional setae; microspinulae restricted to dorsal margin of coxae and ventral

margin of femora; tarsal claws with marginal spinulae restricted to basal 1/2 or less; Neotropical, Palearctic ....... 1514. Antenna < 1.10 times as long as HW and < 1.60 times as long as length of maxillary palpus; metathoracic legs <

2.90 times as long as HW; profemur with 3 anteroventral additional setae; body colour yellowish grey .R. suturellus- Antenna > 1.20 times as long as HW and > 1.70 times as long as length of maxillary palpus; metathoracic legs >

3.10 times as long as HW; profemur with 4 anteroventral additional setae; body colour predominantly greyish black ......................................................................................................................................................................... R. wallisi

15. Primary seta UR4 shorter than any of setae UR5, UR6, UR8 (Fig. 151); tibiae lacking posteroventral additional setae(Fig. 149); pro- and mesofemora with at most 3 anteroventral additional setae; antennomere IV < 1.00 times as longas HW; maxillary palpomere III > 1.30 times as long as maxillary palpomere II; smaller species, HL < 0.90 mm;Neotropical.................................................................................................................................................... R. signatus

- Primary seta UR4 subequal or longer than any of setae UR5, UR6, UR8 (Figs 70, 80, 90); tibiae with at least 1posteroventral additional seta (Figs 68, 78, 88); pro- and mesofemora with at least 4 anteroventral additional setae;



antennomere IV > 1.10 times as long as HW; maxillary palpomere III < 1.20 times as long as maxillary palpomereII; larger species, HL > 1.10 mm; Palearctic .............................................................................................................. 16

16. Stipes with at least 1 additional seta along inner margin; urogomphi > 2.00 times as long as length of last abdominalsegment, with microspinulae over proximal 1/2; antennae > 1.30 times as long as HW; mandible < 2.50 times aslong as broad; metathoracic legs > 3.30 times as long as HW .................................................................. R. exsoletus

- Stipes lacking additional setae along inner margin; urogomphi < 1.70 times as long as length of last abdominalsegment, with microspinulae over the entire surface; antennae < 1.10 times as long as HW; mandible > 2.60 times aslong as broad; metathoracic legs < 3.20 times as long as HW .................................................................................. 17

17. Lamellae clypeales spatulate; procoxal seta CO7 articulated proximally to articulation of seta CO6; tarsi with at least2 ventral additional setae (Figs 87–88); antenna about 1.30 times as long as maxillary palpus; antennomere IV >1.80 times as long as antennomere I and > 1.20 times as long as antennomere III; mandible about 3.0 times as longas broad ......................................................................................................................................................... R. fennicus

- Lamellae clypeales spiniform or digitiform; procoxal seta CO7 articulated distally, at about level of articulation ofseta CO6; tarsi with at most one ventral additional seta (Figs 67–68); antenna about 1.60 times as long as maxillarypalpus; antennomere IV < 1.50 times as long as antennomere I and < 1.00 times as long as antennomere III;mandible about 2.70 times as long as broad ..............................................................................................R. consputus

18. Urogomphi lacking secondary setae (Figs 19, 50, 136)............................................................................................. 19- Urogomphi with secondary setae (e.g., Fig. 29) ........................................................................................................ 2219. Stipes with 3 elongate hook-like spiniform setae along inner margin; lamellae clypeales spiniform to digitiform;

antennomeres II–IV (Fig. 46), maxillary palpomeres II–III and labial palpomere I fractured proximally (best seenunder compound microscope); abdominal segment 8 elongate, > 1.30 times as long as HW; urogomphus short, <0.30 times as long as last abdominal segment; protarsus with > 40 natatory setae; Nearctic/Neotropical ... R. calidus

- Stipes with only minute setae along inner margin; lamellae clypeales spatulate; antennomeres II–IV, maxillarypalpomeres II–III and labial palpomere I not fractured proximally; abdominal segment 8 shorter, < 1.20 times aslong as HW; urogomphus longer, > 0.70 times as long as last abdominal segment; protarsus with < 30 natatory setae ..................................................................................................................................................................................... 20

20. HW/OCW > 2.20; antennomere IV < 0.50 times as long as antennomere I; mandible > 3.30 times as long as broad;last abdominal segment shorter, < 0.70 times as long as HW; profemoral, meso- and metatibial and meso- andmetatarsal AV marginal spinulae weakly developed; metathoracic legs < 2.40 times as long as HW; metatibia with >9 PV secondary setae; urogomphi not fractured proximally; Pacific ................................................ R. poellerbauerae

- HW/OCW < 1.60; antennomere IV > 0.90 times as long as antennomere I; mandible < 3.00 times as long as broad;last abdominal segment longer, > 1.00 times as long as HW; profemoral, meso- and metatibial and meso- andmetatarsal AV marginal spinulae strongly developed; metathoracic legs > 2.80 times as long as HW; metatibiae with< 7 AV secondary setae; urogomphi fractured proximally (Figs 19, 136); Neotropical............................................ 21

21. Stipes lacking microspinulae along inner margin; antenna about 1.60 times as long as maxillary palpus; mesofemurwith < 40 natatory setae; meso- and metatarsi lacking PV secondary setae; metatibia with < 40 natatory setae;smaller species, HL < 2.90 mm .................................................................................................................... R. orbignyi

- Stipes with microspinulae along inner margin; antenna about 1.40 times as long as maxillary palpus; mesofemurwith > 50 natatory setae; meso- and metatarsi with at least 4 PV secondary setae; metatibia with > 45 natatory setae;larger species, HL > 3.10 mm .....................................................................................................R. antarcticus nahueli

22. Galea elongate, about 0.80 times as long as maxillary palpomere I; adnasaliae diverging outward (Fig. 107); mostanterior secondary temporal spine-like setae articulated at about level of occipital region (Fig. 107); antennomere IIIlacking a ventroapical spinula; maxillary palpomere III > 1.10 times as long as maxillary palpomere II; metathoraciclegs about 3.30 times as long as HW; mesofemur with < 15 natatory setae; metatibia with < 20 natatory setae;Palearctic.......................................................................................................................................................... R. grapii

- Galea shorter, < 0.50 times as long as maxillary palpomere I; adnasaliae converging inward (e.g., Fig. 25); mostanterior secondary temporal spine-like setae articulated at about level of ocularium (e.g., Fig. 25); antennomere IIIwith a ventroapical spinula; maxillary palpomere III < 1.00 times as long as maxillary palpomere II; metathoraciclegs < 3.00 times as long as HW; mesofemur with > 20 natatory setae; metatibia with > 22 natatory setae............. 23

23 Outer margin of urogomphi with elongate hair-like setae only, except for one short spine-like seta proximally (Figs75, 85, 95, 116, 126, 161, 176, 186 200, 210) ............................................................................................................ 24

- Outer margin of urogomphi with a variable number of hair-like and spine-like setae (Figs 29, 39, 60, 65, 100, 146,156, 171) .................................................................................................................................................................... 34



24. Inner margin of urogomphi lacking secondary setae; last abdominal segment < 0.70 times as long as HW;antennomere IV about 0.60 times as long as antennomere I; maxillary palpus about 1.40 times as long as labialpalpus; HW/OCW about 2.10; metathoracic legs about 2.30 times as long as HW; meso- and metatibial andmetatarsal marginal spinulae weakly developed, almost lacking; mesofemur with > 30 PV secondary setae;mesotarsus with > 12 PV secondary setae; metafemur with > 40 D spine-like secondary setae; larger species, HL =3.80 mm; Pacific ......................................................................................................................................... R. monteithi

- Inner margin of urogomphi with secondary setae; last abdominal segment > 0.90 times as long as HW; antennomere IV > 0.70 times as long as antennomere I; maxillary palpus < 1.20 times as long as labial palpus; HW/OCW < 2.00;metathoracic legs > 2.50 times as long as HW; meso- and metatibial and metatarsal marginal spinulae stronglydeveloped; mesofemur with < 20PV secondary setae; mesotarsus with < 8 PV secondary setae; metafemur with < 30D spine-like secondary setae; smaller species, HL < 3.50 mm ................................................................................. 25

25. Dorsal secondary setae of coxae predominantly short (Figs 83, 93, 114, 174), if not, metafemoral natatory setaearticulated over distal 2/3 to 3/4 of dorsal margin; Palearctic .................................................................................... 26

- Dorsal secondary setae of coxae predominantly elongate (Figs 73, 159, 184, 198, 208); metafemoral natatory setaearticulated over distal 1/2 of dorsal margin Australian, Nearctic, Neotropical, Palearctic ........................................ 30

26. Antenna < 1.30 times as long as maxillary palpus; mandible > 3.20 times as long as broad; profemur with > 30 AVand > 15 PV secondary setae (Figs 92–93); mesofemur with < 8 PV secondary setae .............................. R. fennicus

- Antenna > 1.60 times as long as maxillary palpus; mandible < 3.00 times as long as broad; profemur with < 28 AVand < 13 PV secondary setae (Figs 82–83, 113–114, 123–124); mesofemur with > 10 PV secondary setae ........... 27

27. Urogomphi shorter, < 0.80 times as long as last abdominal segment ............................................................R. latitans- Urogomphi longer, > 1.00 times as long as last abdominal segment ......................................................................... 2828. Antenna > 0.90 times as long as HW; urogomphi > 1.30 times as long as HW......................................... R. exsoletus- Antenna < 0.80 times as long as HW; urogomphi < 1.20 times as long as HW......................................................... 2929. HL > 2.60 mm; urogomphus > 2.70 mm; L3 > 6.90 mm; A4/A1 > 0.90; tarsi with PV secondary setae; protrochanter

with > 3 secondary setae .......................................................................................................................... R. notaticollis- HL < 2.50 mm; urogomphus < 2.50 mm; L3 < 6.20 mm; A4/A1 < 0.80; tarsi lacking PV secondary setae;

protrochanter with 1 secondary seta .............................................................................................................R. suturalis30. Stipes with 3 elongate hook-like setae along inner margin; prementum with elongate setae along anterior margin

(e.g., Fig. 194); antenna < 1.30 times as long as HW; profemoral anteroventral marginal spinulae weakly developed,almost lacking (Fig. 197); urogomphus not fractured proximally (Fig. 200); meso- and metacoxae with > 50secondary setae; trochantera with > 7 secondary setae; pro- and metatibiae with > 8 PV secondary setae; largerspecies, HL = 3.50 mm; Neotropical ............................................................................................................. R. validus

- Stipes with 2–3 minute setae along inner margin; prementum with minute setae along anterior margin (e.g., Fig. 7);antenna > 1.50 times as long as HW; profemoral anteroventral marginal spinulae strongly developed (e.g., Fig.207); urogomphus fractured proximally (e.g., Fig. 210); meso- and metacoxae with < 40 secondary setae;trochantera with < 6 secondary setae; pro- and metatibiae with < 7 PV secondary setae; smaller species, HL < 3.00mm; Australian, Nearctic, Palearctic ........................................................................................................................ 31

31. Microspinulae present along inner margin of stipes; meso- and metatarsi lacking PV secondary setae; Australian .......................................................................................................................................................................... R. simulans

- Microspinulae lacking along inner margin of stipes; meso- and metatarsi with > 3 PV secondary setae; Nearctic,Palearctic.................................................................................................................................................................... 32

32. Pro-, meso- and metatibia with > 33, 39 and 39 natatory setae, respectively; mesofemur with > 26 AV secondarysetae; meso- and metatibiae with > 15 and 17 AV secondary setae, respectively; Palearctic ...................R. consputus

- Pro-, meso- and metatibia with < 29, 35 and 33 natatory setae, respectively: mesofemur with < 20 AV secondarysetae; meso- and metatibiae with < 10 and 12 AV secondary setae, respectively; Nearctic or Holarctic .................. 33

33. Protarsus with < 21 natatory setae (Fig. 184); meso- and metafemur with < 27 and 9 natatory setae, respectively;metatibia with < 28 natatory setae; body predominantly black ................................................................. R. suturellus

- Protarsus with > 23 natatory setae (Fig. 208); meso- and metafemur with > 29 and 12 natatory setae, respectively;metatibia with > 31 natatory setae; body predominantly yellowish ............................................................... R. wallisi

34. Outer margin of urogomphus with spine-like secondary setae only; metatarsal ventral spinulae weakly developed,almost lacking; metathoracic legs < 2.50 times as long as HW; Palearctic .............................................R. formosanus

- Outer margin of urogomphus with a variable number of spine-like and hair-like secondary setae (e.g., Fig. 65);metatarsal ventral spinulae strongly developed (e.g., Fig. 62); metathoracic legs > 2.60 times as long as HW;African, Nearctic, Neotropical, Palearctic ................................................................................................................. 35



35. Afrotropical species .................................................................................................................................................... 36- Nearctic, Neotropical, Palearctic species ................................................................................................................... 3836. Urogomphi < 1.40 times as long as last abdominal segment; lamellae clypeales spiniform to digitiform; profemoral

ventral spinulae well-developed (Fig. 62); metafemur with natatory setae over distal 3/4 of dorsal margin; lastabdominal segment about 0.90 times as long as HW .................................................................................. R. capensis

- Urogomphi > 1.85 times as long as last abdominal segment; lamellae clypeales spatulate; profemoral ventralspinulae weakly developed, almost lacking (Figs 143, 168); metafemur with natatory setae at most over distal 1/2 ofdorsal margin; abdominal segment < 0.70 times as long as HW ............................................................................... 37

37. Microspinulae present along inner margin of stipes; meso- and metatibial ventral spinulae weakly developed orlacking; profemur with < 14 AV secondary setae (Fig. 168); metatibia with < 9 AV secondary setae ......... R. socialis

- Microspinulae lacking along inner margin of stipes; meso- and metatibial ventral spinulae strongly developed;profemur with > 21 AV secondary setae (Fig. 143); metatibia with > 11 AV secondary setae ............R. phocaenarum

38. Last abdominal segment longer, about 1.20 times as long as HW; Palearctic ............................................ R. frontalis- Last abdominal segment shorter, < 1.00 times as long as HW; Nearctic, Neotropical .............................................. 3939. Profemoral and metatibial ventral spinulae weakly developed or lacking (Fig. 57); mesofemur with > 50 natatory

setae; metatibia with > 40 natatory setae; Neotropical .............................................................................. R. calileguai- Profemoral and metatibial ventral spinulae strongly developed; mesofemur with < 35 natatory setae; metatibia with

< 36 natatory setae ..................................................................................................................................................... 4040. Microspinulae present along inner margin of stipes; protibia with > 27 natatory setae (Fig. 27); Nearctic/Neotropical

................................................................................................................................................................ R. anisonychus- Microspinulae lacking along inner margin of stipes; protibia with < 25 natatory setae (Figs 37, 154) .................... 4141. Metafemur with > 15 PV secondary setae; Nearctic................................................................................... R. binotatus- Metafemur with < 11 PV secondary setae; Neotropical ............................................................................. R. signatus

Description of larvae of Rhantus antarcticus nahueli Trémouilles, 1984

Source of material. The larvae studied were both reared ex ovo and collected in association with adults at thefollowing localities. Argentina, Chubut Province. 1) Aldea Escolar, Laguna Seca (INTA experimentalstation), 450 masl, 3.XI.2003; 2) stream arising from Laguna La Z, surroundings of Esquel City, 2003, M.Archangelsky & M.C. Michat, leg.

First-instar larva (n = 6) (Figs 1–14)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Dorsal surface of cephalic capsule dark brown except for one light brown macula enclosing each

egg burster; ventral surface dark brown except for a narrow, longitudinal, light brown band centrally; headappendages brown except for distal 1/2 of mandible yellowish; thoracic and abdominal tergites brown; legsbrown except for coxa somewhat paler and medial portion of trochanter testaceous; urogomphus brown.

Head (Figs 1–9). Head capsule (Figs 1–2). Frontoclypeus extending beyond tips of adnasaliae, lackingmicrospinulae over dorsal surface; adnasaliae converging inward; occipital carina well defined; parietaledistinctly constricted at level of occipital region, with microspinulae reduced, covering posterior 1/2 of dorsalsurface. Antenna (Figs 3–4). Microspinulae lacking, antennomere III with a ventroapical spinula. Maxilla(Figs 5–6). Palpus lacking microspinulae. Labium (Figs 7–8). Palpus lacking microspinulae.

Thorax. Legs (Figs 10–11). Microspinulae restricted to dorsal margin of coxae and ventral margin offemora, tibiae and tarsi; tarsal claws with microspinulae covering basal 3/4 of ventral margin.

Abdomen. Urogomphus (Fig. 14). Microspinulae reduced, almost lacking.Chaetotaxy. Position and number of additional setae on legs are shown in Table 4; primary pore FRe

lacking (Fig. 1); anterior margin of frontoclypeus with 27–31 spiniform to digitiform lamellae clypeales (Fig.1); A3 with two additional ventroapical pores (Fig. 4); primary seta MX7 shorter than galea (Fig. 6); primaryseta MX5 shorter than palpifer and galea (Fig. 5); stipes lacking additional setae along inner margin (Figs 5–6); anterodorsal primary setae of prementum minute (Fig. 7); procoxal seta CO7 articulated distally, at aboutlevel of seta CO6; meso- and metafemoral seta FE5 short and spine-like (Fig. 11); seta TI7 short and spine-



like (Fig. 11); urogomphus (Fig. 14) with one additional seta; primary seta UR2 about as long as seta UR3;primary seta UR4 as long as any of setae UR5, UR6 or UR8; seta UR5 articulated posteriorly to articulation ofseta UR7; seta UR7 as long as any of setae UR5, UR6 or UR8.

Second-instar larva (n = 6)As first-instar larva except as follows:Colour. Dorsal surface of cephalic capsule dark brown dorsally except for one dorsal, light brown macula

posterior to each lateral margin of frontoclypeus; head appendages brown except for distal 1/2 of mandiblereddish brown; urogomphus light brown.

Head. Maxilla. Microspinulae lacking along inner margin of stipes.Thorax. Legs. Anteroventral spinulae strongly developed on profemora, tibiae and tarsi; metacoxa with

several elongate hair-like secondary setae along dorsal margin (cf. Fig. 17); metafemoral natatory setaepresent along distal 1/2 of dorsal margin.

Abdomen. Urogomphus. Fractured proximally (cf. Fig. 19).Chaetotaxy. Number and position of secondary setae on legs are shown in Table 5; parietale with 8–9

temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith minute secondary setae along inner margin; dorsal surface of last abdominal segment covered with bothspine-like and hair-like secondary setae (cf. Fig. 18); urogomphus lacking secondary setae (cf. Fig. 19).Measurements and ratios aimed to characterize body shape shown in Table 10.

Third-instar larva (n = 6) (Figs 15–19)As second-instar larva except as follows:Colour. Dorsal surface of cephalic capsule light brown except for several small lighter maculae on central

portion of frontoclypeus, posterior to stemmata, anterior to occipital suture and medial to each ocular area(Fig. 15); head appendages light brown except for distal 1/2 of mandible reddish; thoracic and abdominaltergites light brown; membranous parts testaceous; legs light brown; urogomphus yellowish.

Chaetotaxy. Number and position of secondary setae on legs are shown in Table 7 (Figs 16–17); parietalewith 8–9 temporal spine-like setae.

Measurements and ratios aimed to characterize body shape shown in Table 11.

Remarks. Larvae of this Neotropical species are characterized by the following unusual features inRhantus: absence of primary pore FRe (best seen in first instar) (Fig. 1), short and spine-like condition ofmeso- and metafemoral primary setae FE5 and TI7 (first instar) (Fig. 11), absence of additional setae onprotibiae and tarsi (first instar) (Table 4), and absence of secondary setae on urogomphus (Fig. 19). Suchcombination of characters is found in only two other species of Rhantus, namely R. calidus (Fabricius, 1792)and R. orbignyi. It is noteworthy that all these three species are found in the Neotropical region. Larvae of R.antarcticus nahueli can readily be distinguished from the other two species of this group by the followingcombination of characters: larger size, absence of microspinulae along inner margin of stipes (second- andthird instars), number of PV secondary setae on meso- and metatarsi and natatory setae on metatibia (Tables 5,7), relative length of LAS and urogomphus compared to HW, larger number of lamellae clypeales (> 27compared to < 16 in first instar), lamellae clypeales spatulate (first instar), presence of additional setae onmesotibiae (first instar) (Table 4), and primary seta UR7 subequal in length to any of setae UR5, UR6, andUR8 (first instar) (Fig. 14) (see also under R. calidus and R. orbignyi).

Description of larvae of Rhantus anisonychus Crotch, 1873

Source of material. The larvae studied were reared ex ovo from adults collected at the following locality:USA. California, Riverside Co. Elsimore Lake, pond at HWY 74, 15.III.2000, Y. Alarie, leg. Associatedlarvae from the same locality were also used in this study.



First-instar larva (n = 7) (Figs 20–24)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Overall predominantly greyish black; head appendages, legs and urogomphus slightly paler

(freshly killed larvae).Head. Head capsule (Fig. 20). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulae

over dorsal surface; adnasaliae converging inward; occipital carina well defined; parietale slightly constrictedat level of occipital region, with microspinulae covering posterior 2/3 of dorsal surface. Antenna.Microspinulae present over most of dorsal surface, antennomere III with a ventroapical spinula. Maxilla.Palpus with microspinulae present over most of dorsal surface. Labium. Palpus with microspinulae presentover most of dorsal surface.

Thorax. Legs (Fig. 21–22) Microspinulae present over most of anterior surface; tarsal claws withmicrospinulae covering basal 1/3 to 1/2 of ventral margin.

Abdomen. Urogomphus (Fig. 24). Microspinulae present over most of dorsal surface.Chaetotaxy. Position and number of additional setae on legs are shown in Table 4; primary pore FRe

present; anterior margin of frontoclypeus with 24–25 spiniform to digitiform lamellae clypeales; A3 with twoadditional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorter than palpiferand galea; stipes lacking additional setae along inner margin; anterodorsal primary setae of prementumminute; procoxal seta CO7 articulated distally, at about level of seta CO6; meso- and metafemoral seta FE5elongate and hair-like (Fig. 22); seta TI7 elongate and hair-like (Fig. 22); urogomphus (Fig. 24) with oneadditional seta; primary seta UR2 about as long as seta UR3; primary seta UR4 shorter than any of setae UR5,UR6 or UR8; seta UR5 articulated posterior to articulation of seta UR7; seta UR7 shorter than any of setaeUR5, UR6 or UR8.

Second-instar larva (n = 3)As first-instar larva except as follows:Head. Maxilla. Microspinulae present along inner margin of stipes.Thorax. Legs. Anteroventral spinulae strongly developed on profemora, tibiae and tarsi; metacoxa with

several elongate hair-like secondary setae along dorsal margin (cf. Fig. 27); metafemoral natatory setaepresent along distal 1/2 of dorsal margin.


temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith minute secondary setae along inner margin; dorsal surface of last abdominal segment covered with bothspine-like and hair-like secondary setae (cf. Fig. 28); urogomphus with secondary setae along both inner andouter margins, outer margin with variable number of hair-like and spine-like secondary setae (cf. Fig. 29).


Third-instar larva (n = 9) (Figs 25–29)As second-instar larva except as follows:Colour. Head capsule with an irrorate colour pattern (Fig. 25); thoracic terga with variable number of

testaceous maculae; legs dark yellow to pale brown; urogomphus dark yellow to pale brown.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 7 and Figs 26–27;

parietale with 11–13 temporal spine-like setae.Measurements and ratios aimed to characterize body shape shown in Table 11.

Remarks. Rhantus anisonychus groups with those species characterized by the presence of a variablenumber of elongate hair-like and short spine-like secondary setae along outer margin of urogomphus (Fig. 29)(i.e., R. signatus, R. frontalis (Marsham, 1802), R. capensis (Aubé, 1838), R. binotatus Harris, 1828, R.calileguai, R. socialis (C.O. Waterhouse, 1876), R. phocaenarum). Second- and third-instar larvae of R.



anisonychus can readily be distinguished from any species of this group both by a relatively longer maxillarypalpus and shorter urogomphus compared to HW (Tables 10, 11). As first-instar larva R. anisonychus can berecognized by the presence of microspinulae on the head appendages and by the distal articulation of theprocoxal seta CO7.

Description of larvae of Rhantus binotatus (Harris, 1828)

Source of material. The larvae studied were reared ex ovo from adults collected by Y. Alarie at the followinglocalities: Canada. British Columbia. Duteau Creek, 5 km west of Lumby, Hwy 6, 31.V.1992. Ontario,Manitoulin Island. Creek at Hwy 540, 21 km west of Little Current, 28.V. 1998, 10.VI.1998. USA.Colorado. Jefferson Co. Pike National Forest. FR211, off road 77, 6 minutes north of Hwy 24, close to LakeGeorge, 08.V.1998.

First-instar larva (n = 2) (Figs 30–34)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Overall predominantly greyish black (freshly killed larvae).Head. Head capsule (Fig. 30). Frontoclypeus extending beyond tips of adnasaliae, with microspinulae

over whole dorsal surface; adnasaliae converging inward; occipital carina well defined; parietale slightlyconstricted at level of occipital region, with microspinulae over whole dorsal surface. Antenna. Microspinulaeover most of dorsal surface, A3 with a ventroapical spinula. Maxilla. Palpus with microspinulae over most ofdorsal surface. Labium. Palpus with microspinulae over most of dorsal surface.

Thorax. Legs (Figs 31–32). Microspinulae present over most of anterior surface; ventral margin of tarsalclaws with microspinulae over basal 1/2.


present (Fig. 30); anterior margin of frontoclypeus with 19–20 spiniform to digitiform lamellae clypeales (Fig.30); A3 with two additional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5shorter than palpifer and galea; stipes lacking additional setae along inner margin; anterodorsal primary setaeof prementum minute; procoxal seta CO7 articulated proximally to articulation of seta CO6; meso- andmetafemoral seta FE5 elongate and hair-like (Fig. 32); seta TI7 elongate and hair-like (Fig. 32); urogomphus(Fig. 34) with one additional seta; primary seta UR2 about as long as seta UR3; primary seta UR4 shorter thanany of setae UR5, UR6 or UR8; seta UR5 articulated posterior to articulation of seta UR7; seta UR7 shorterthan any of setae UR5, UR6 or UR8.

Second-instar larva (n = 2)As first-instar larva except as follows:Colour. Body yellowish with an irrorate greyish pattern; head appendages piceous, articles infuscate

apically; thoracic and abdominal terga I to VI yellowish with a faint greyish pattern and with a narrowblackish stripe mesally; abdominal terga VII and VIII piceous; legs and urogomphi creamy white to paleyellow.

Head. Maxilla. Microspinulae lacking along inner margin of stipes.Thorax. Legs. Microspinulae present along anteroventral margin of profemur, tibiae and tarsi; metacoxa

with several elongate hair-like secondary setae along dorsal margin (cf. Fig. 37); metafemoral natatory setaealong distal 1/2 of dorsal margin.


temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith minute secondary setae along inner margin; dorsal surface of last abdominal segment covered with both



spine-like and hair-like secondary setae (cf. Fig. 38); urogomphus with secondary setae along both inner andouter margins, outer margin with a variable number of hair-like and spine-like secondary setae (cf. Fig. 39).


Third-instar larva (n = 9) (Figs 35–39)As second-instar larva except as follows:Colour. Head appendages predominantly yellowish except A4 and MP3 and apices of A2, A3, MP2 and

LP1 piceous.Thorax. Legs (Figs 36–37). Metafemoral natatory setae along distal 1/2 to 3/4 of dorsal margin.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 7 (Figs 36–37); parietale

with 7–9 temporal spine-like setae.Measurements and ratios aimed to characterize body shape shown in Table 11.

Remarks. Second- and third instar of R. binotatus are characterized by the presence of a variable number ofelongate hair-like setae and short spine-like setae along outer margin of urogomphus (Fig. 39), a conditionfound also in R. signatus, R. frontalis, R. capensis, R.anisonychus, R. calileguai, R. socialis and R.phocaenarum. Compared to these species, larvae of R. binotatus can only be confounded to those of R.anisonychus also found in the Nearctic region. Larvae of R. binotatus can readily be distinguished from thelatter by the following combination of features: smaller size, slightly longer urogomphus (compared either toHW or LAS), absence of microspinulae along inner margin of stipes (second- and third instar), and the moreproximal articulation of the procoxal seta CO7 (first instar).

Description of larvae of Rhantus calidus (Fabricius, 1792)

Source of material. The larvae studied were collected in association with adults by Y. Alarie and Y. S. Megna(Universidad de Oriente) at the following locality: Cuba: Santiago de Cuba, Campo Rico II, 03.V.2005. Theidentification is firm as R. calidus is the only Rhantus species known from Cuba.

First-instar larva (n = 1) (Figs 40–44)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Body predominantly piceous black.Head. Head capsule (Fig. 40). Frontoclypeus extending at most at level of tips of adnasaliae, lacking

microspinulae over dorsal surface; adnasaliae converging inward; occipital carina well defined; parietaledistinctly constricted at level of occipital region, with microspinulae over posterior 2/3 of dorsal surface.Antenna. Lacking microspinulae, A3 with a ventroapical spinula. Maxilla. Palpus lacking microspinulae.Labium. Palpus lacking microspinulae.

Thorax. Legs (Figs 41–42). Microspinulae present over most of anterior surface; ventral margin of tarsalclaws with microspinulae along basal 1/4 to 1/3.


lacking (Fig. 40); anterior margin of frontoclypeus with 16 spiniform lamellae clypeales; A3 lackingadditional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorter than palpiferand galea; stipes with one additional seta on inner margin; anterodorsal primary setae of prementum minute;procoxal seta CO7 articulated distally, at about level of articulation of seta CO6; meso- and metafemoral setaFE5 short and spine-like (Fig. 42); seta TI7 short and spine-like (Fig. 42); urogomphus (Fig. 44) with oneadditional seta; primary seta UR2 about as long as seta UR3; primary seta UR4 shorter than any of setae UR5,UR6 or UR8; seta UR5 articulated anterior to articulation of seta UR7; seta UR7 shorter than any of setaeUR5, UR6 or UR8.



Second-instar larva (n = 8)As first-instar larva except as follows:Colour. Head capsule with a few yellowish maculae; legs paler; urogomphus yellowish.Head. Maxilla. Microspinulae present along inner margin of stipes.Thorax. Legs. Anteroventral spinulae weakly developed on profemur, more strongly developed on tibiae

and tarsi; metacoxa with several elongate hair-like secondary setae along dorsal margin (cf. Fig. 48);metafemoral natatory setae present along distal 1/2 of dorsal margin.

Abdomen. Urogomphus. Not fractured proximally (cf. Fig. 50).Chaetotaxy. Number and position of secondary setae on legs are shown in Table 5; parietale with 6–11

temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith three elongate hook-like secondary setae along inner margin; dorsal surface of last abdominal segmentcovered with both spine-like and hair-like secondary setae (cf. Fig. 49); urogomphus lacking secondary setae(cf. Fig. 50).


Third-instar larva (n = 1) (Figs 45–50)As second-instar larva except as follows:Colour. Head capsule (Fig. 45) predominantly yellowish; frontoclypeus with a reticulate dark brown

macula mesally; parietale with a dark brown macula mesally and a reticulate dark brown pattern posteriorly;A2, A3, A4, MP2, MP3 and LP2 with a narrow piceous band proximally; thoracic terga piceous with darkyellow maculae; abdominal terga I to VI piceous with a dark yellow maculation pattern; abdominal segmentsVII and VIII paler; legs dark yellow.

Head. Antenna (Fig. 46). A2–A4 secondarily subdivided proximally. Maxilla. MP2 and MP3 secondarilysubdivided proximally. Labium. LP2 secondarily subdivided proximally.

Thorax. Legs (Figs 47–48). Metafemoral natatory setae along distal ¾ of dorsal margin.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 7 and Figs 47–48;


Remarks. Third-instar larvae of R. calidus are unique within the genus Rhantus in that A2, A3, A4, MP2,MP3 and LP2 are fractured proximally (best seen under a compound microscope). Compared to the otherspecies studied, larvae of R. calidus are characterized by the absence of secondary setae on urogomphus, afeature also found in larvae of R. antarcticus nahueli (cf. above), R. orbignyi (cf. below), and R.poellerbauerae (Balke et al. 2007). Rhantus calidus can readily be distinguished from any of these species bythe following combination of characters: anterior margin of frontoclypeus at most extending to level of tips ofadnasaliae, A3 lacking anteroventral additional pores, protarsus and metatibia with a larger number ofnatatory setae (Tables 5, 7), and much shorter urogomphus (Tables 9–11) (see also under R. antarcticusnahueli and R. orbignyi).

The third-instar larva of R. calidus was previously described by Crespo (1987) and Costa et al. (1988).

Description of larvae of Rhantus calileguai Trémouilles, 1984

Source of material. The larvae studied were collected in association with adults by M. Archangesky and M.CMichat at the following locality: Argentina, Jujuy Province, pond at Yala-Termas de Reyes road (about 2000masl), 25/26.XI.2003. Larvae found in an elongate pond about two meters width, 30 m long and 20 cm deepwith some vegetation. It was placed near a shaded stream in a mountainous forested area. No other Rhantusspecies was collected at that site.



First-instar larva (n = 6) (Figs 51–55)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Dorsal surface of head dark brown except for a light brown macula enclosing each egg burster;

ventral surface light brown except for a narrow, longitudinal, yellowish band centrally; head appendagesgreyish to light brown, A1 and apices of A3, A4, MP3 and LP2 brown; thoracic and abdominal sclerites lightbrown, membranous parts yellowish; leg segments yellowish, dorsal surface light brown; urogomphus greyishto pale brown.

Head. Head capsule (Fig. 51). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulaeover dorsal surface; adnasaliae converging inward; occipital carina well defined; parietale distinctlyconstricted at level of occipital region, with microspinulae over whole dorsal surface. Antenna. Microspinulaelacking, A3 with a ventroapical spinula. Maxilla. Palpus lacking microspinulae. Labium. Palpus lackingmicrospinulae.

Thorax. Legs (Figs 52–53). Microspinulae present over most of anterior surface; tarsal claws withmicrospinulae present over basal 1/4 of ventral margin.


present (Fig. 51); anterior margin of frontoclypeus with 19–22 spiniform lamellae clypeales; A3 with twoadditional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorter than palpiferand galea; stipes lacking additional setae along inner margin; anterodorsal primary setae of prementumminute; procoxal seta CO7 articulated distally, at about level of articulation of seta CO6; meso- andmetafemoral seta FE5 elongate and hair-like (Fig. 53); seta TI7 elongate and hair-like (Fig. 53); urogomphus(Fig. 55) with one additional seta; primary seta UR2 about as long as seta UR3; primary seta UR4 shorter thanany of setae UR5, UR6 or UR8; seta UR5 articulated posterior to articulation of seta UR7; seta UR7 shorterthan any of setae UR5, UR6 or UR8.

Second-instar larva (n = 3)As first-instar larva except as follows:Colour. Dorsal surface of head light brown except for anterior and lateral margins and several small

maculae on central portion of FR, posterior to stemmata, anterior to occipital suture and medial to each oculararea yellowish; ventral surface yellowish; head appendages yellowish, apex of LP2 light brown; thoracic and,to a lesser extent abdominal sclerites with a pattern of yellowish maculae on a greyish to light brownbackground; membranous parts, legs and U yellowish.

Head. Maxilla. Microspinulae present along inner margin of stipes.Thorax. Legs. Anteroventral spinulae weakly developed on profemur, more strongly developed on tibiae

and tarsi; metacoxa with several elongate hair-like secondary setae along dorsal margin; metafemoral natatorysetae present along distal 1/2 of dorsal margin.


temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith minute secondary setae along inner margin; dorsal surface of last abdominal segment covered with bothspine-like and hair-like secondary setae (cf. Fig. 59); urogomphus with secondary setae along both inner andouter margins, outer margin with a variable number of hair-like and spine-like secondary setae (cf. Fig. 60).


Third-instar larva (n = 3) (Figs 56–60)As second-instar larva except as follows:Colour. Dorsal surface of head reddish to light brown except for several maculae on central portion of FR,

posterior to stemmata, anterior to occipital suture and medial to each ocular area yellowish (Fig. 56); ventralsurface dark yellow except for posterolateral areas reddish to light brown bearing several small dark yellow



maculae; head appendages yellowish except for apices of MP3 and LP2 light brown and distal 1/2 of MN darkbrown; thoracic and abdominal sclerites reddish to light brown, with pattern of dark yellow maculae, scleritesVII and VIII without this pattern; membranous parts testaceous; legs yellow to reddish; urogomphus paleyellowish.

Thorax. Legs (Figs 57–58). Metafemoral natatory setae present along distal 1/2 to 3/4 of dorsal margin.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 7 and Figs 57–58;


Remarks. Second- and third-instar larvae of this Neotropical species are characterized by the presence of avariable number of elongate hair-like and short spine-like secondary setae along the inner margin ofurogomphus. This character state is also found in R. anisonychus and R. signatus, both distributed in theNeotropical region. Larvae of R. calileguai can readily be distinguished from those of any of these twospecies by the following combination of characters: larger size, presence of microspinulae along inner marginof stipes (second- and third instar), anteroventral marginal spinulae weakly developed on profemur (second-and third instar) (Figs 57–58), larger number of natatory setae on mesofemur and metatibia (Tables 5, 7),shorter LAS and longer urogomphus compared to HW (Tables 9–11).

Description of larvae of Rhantus capensis (Aubé, 1838)

Source of material. The single third-instar larva studied was collected by S. Persson in association withadults at the following locality: Ethiopia, Arsi province, Bekoji, 10.XI.1988. No other Rhantus species wascollected in this temporary pool at 2800 m asl.

First- and second instar larvaeNo specimens available for study.

Third-instar larva (n = 1) (Figs 61–65)Measurements and ratios aimed to characterize body shape shown in Table 11.Colour. Body predominantly dark yellow to pale brown; head capsule dark yellow with a dark brown

reticulate pattern mesally over frontoclypeus and parietale (Fig. 61); head appendages yellow, most articlesinfuscate apically; body terga predominantly dark yellow to pale brown; thoracic and abdominal terga I to VIinfuscate along posterior margin; legs and urogomphus yellowish.

Head. Maxilla. Microspinulae lacking along inner margin of stipes.Thorax. Legs (Figs 62–63). Anteroventral spinulae strongly developed on profemur, tibiae and tarsi;

metacoxa with dorsal secondary setae predominantly short; metafemoral natatory setae present along distal 2/3 to 3/4 of dorsal margin.

Abdomen. Urogomphus (Fig. 65). Fractured proximally.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 7 and Figs 62–63;

parietale with 10 temporal spine-like setae, most anterior ones articulated at about level of posterior margin ofocularium; stipes with minute secondary setae along inner margin; dorsal surface of last abdominal segmentcovered with both spine-like and hair-like secondary setae (Fig. 64); urogomphus with secondary setae alongboth inner and outer margins, outer margin with a variable number of hair-like and spine-like secondary setae(Fig. 65).

Remarks. The third-instar larva of the Afrotropical species R. capensis is characterized by the presenceof a variable number of elongate hair-like setae and short spine-like setae along outer margin of urogomphus(Fig. 65), which is similar to the condition observed in R. signatus, R. frontalis, R. binotatus, R. anisonychus,R. calileguai, R. socialis and R. phocaenarum. Compared to the other African species studied (i.e., R.



phocaenarum and R. socialis) the third-instar larva of R. capensis is readily distinguished by the followingcombination of characters: larger size, microspinulae lacking along inner margin of stipes, anteroventralmarginal spinulae weakly developed on profemur, strongly developed on tibiae and tarsi (Figs 62–63),number of natatory setae on metatibia (Table 7), and relative length of LAS and urogomphus (Table 11).

Description of larvae of Rhantus consputus (Sturm, 1834)

Source of material. The studied larvae were reared by F. Kögel from eggs laid in captivity by adultspecimens collected in riverside pools near Ketsch in Germany. The habitat and biology of the species isdescribed in Kögel (1987).

First-instar larva (n = 1) (Figs 66–70)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Body predominantly dark yellow to pale brown.Head. Head capsule (Fig. 66). Frontoclypeus extending beyond level of tips of adnasaliae, lacking

microspinulae over dorsal surface; adnasaliae converging inward; occipital carina well defined; parietaledistinctly constricted at level of occipital region, with microspinulae at most over posterior 1/2 of dorsalsurface. Antenna. Lacking microspinulae, A3 with a ventroapical spinula. Maxilla. Palpus lackingmicrospinulae. Labium. Palpus lacking microspinulae.

Thorax. Legs (Figs 67–68). Microspinulae restricted to dorsal margin of coxae and ventral margin offemora; tarsal claws with microspinulae present over basal 1/2 of ventral margin.


present; anterior margin of frontoclypeus with 21 spiniform to digitiform lamellae clypeales; A3 with twoadditional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorter than palpiferand galea; stipes lacking additional setae along inner margin; anterodorsal primary setae of prementumminute; procoxal seta CO7 articulated distally, at about level of articulation of seta CO6; meso- andmetafemoral seta FE5 elongate and hair-like (Fig. 68); seta TI7 elongate and hair-like (Fig. 68); urogomphus(Fig. 70) with one additional seta; primary seta UR2 about as long as seta UR3; primary seta UR4 as long asor longer than any of setae UR5, UR6 or UR8; seta UR5 articulated posterior to articulation of seta UR7; setaUR7 shorter than any of setae UR5, UR6 or UR8.

Second-instar larva (n = 1)As first-instar larva except as follows:Colour. Head capsule predominantly brown, with a dark brown macula mesally; head appendages brown,

apex of A1, A2, A3, A4, MX2, MX3 and LP2 darker; body terga, legs and urogomphus brownish.Head. Maxilla. Microspinulae present along inner margin of stipes.Thorax. Legs. Anteroventral spinulae well developed on profemur, tibiae and tarsi; metacoxa with several

elongate hair-like secondary setae along dorsal margin; metafemoral natatory setae present along distal 1/2 ofdorsal margin.


temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith minute secondary setae along inner margin; dorsal surface of last abdominal segment covered with bothspine-like and hair-like secondary setae (cf. Fig. 74); urogomphus with secondary setae along inner and outermargins, outer margin with elongate hair-like setae only except for one short spine-like seta proximally (cf.Fig. 75).




Third-instar larva (n = 1) (Figs 71–75)As second-instar larva except as follows:Colour. Paler.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 7 and Figs 72–73;


Remarks. Compared to the other species studied, larvae of the Palearctic species R. consputus resemble thosecharacterized by the presence of elongate hair-like secondary setae and one short spine-like seta along outermargin of urogomphus (i.e., R. validus, R. simulans Régimbart, 1908, R. wallisi Hatch, 1953, R. suturalis(Macleay, W.S.,1825), R. suturellus (Harris, 1828), R. latitans Sharp, 1882, R. notaticollis (Aubé, 1837), R.exsoletus (Forster, 1771), R. fennicus). Compared to other similar species from the Palearctic region (i.e., R.latitans, R. notaticollis, R. exsoletus, R. fennicus, R. suturellus, R. suturalis), larvae of this species can readilybe recognized by the following combination of features: larger size (Tables 9–11), microspinulae present overposterior 1/2 of dorsal surface of parietale and the entire surface of urogomphus (first instar), lamellaeclypeales digitiform (first instar), tarsi with one additional seta (Fig. 67) (first instar), stipes lacking additionalsetae (first instar), procoxal seta CO7 articulated at about level of seta CO6, dorsal secondary setae onmetacoxa predominantly short (second and third instar), number of natatory setae on metatibia (second- andthird instar) (Tables 5, 7); urogomphus not fractured proximally (Fig. 75), presence of at least two secondarysetae on protrochanter and presence of PV secondary setae on tarsi (Tables 7, 8).

The third-instar larva of this species was previously described by Galewski (1963) and Kögel (1987).

Description of larvae of Rhantus exsoletus (Forster, 1771)

Source of material. The larvae studied were collected by A.N. Nilsson in association with adults at thefollowing localities: Sweden, Ångermanland province, Brattfors, small lake, 27.VI.1998, andVästerbotten province, Vännäs, pond 7.VII.1996. First-instar larva (n = 2) (Figs 76–80)

Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Body predominantly brown; head capsule yellowish around ocularia; antenna dark brown except

A4 predominantly yellow, piceous apically; maxillary and labial palpus dark yellow to pale brown, MP2, MP3and LP2 darker apically; legs dark yellow to pale brown; urogomphus dark brown.

Head. Head capsule (Fig. 76). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulaeover dorsal surface; adnasaliae converging inward; occipital carina well defined; parietale distinctlyconstricted at level of occipital region, with microspinulae at most over posterior 1/2 of dorsal surface.Antenna. Microspinulae lacking, A3 with a ventroapical spinula. Maxilla. Palpus lacking microspinulae.Labium. Palpus lacking microspinulae.

Thorax. Legs (Figs 77–78). Microspinulae restricted to dorsal margin of coxae and ventral margin offemora; tarsal claws with microspinulae over basal 1/2 of ventral margin.

Abdomen. Urogomphus (Fig. 80). Microspinulae restricted to basal 1/2 of dorsal surface.Chaetotaxy. Position and number of additional setae on legs are shown in Table 4; primary pore FRe

present (Fig. 76); anterior margin of frontoclypeus with 25 spatulate lamellae clypeales; A3 with twoadditional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorter than palpiferand galea; stipes lacking additional setae along inner margin; anterodorsal primary setae of prementumminute; procoxal seta CO7 articulated distally, at about level of articulation of seta CO6; meso- andmetafemoral seta FE5 elongate and hair-like (Fig. 78); seta TI7 elongate and hair-like (Fig. 78); urogomphus(Fig. 80) with one additional seta; primary seta UR2 about as long as seta UR3; primary seta UR4 about as



long as any of setae UR5, UR6 or UR8; seta UR5 articulated posterior to articulation of seta UR7; seta UR7shorter than any of setae UR5, UR6 or UR8.

Second-instar larva (n = 1)As first-instar larva except as follows:Colour. Frontoclypeus with an irrorate brownish macula mesally; head appendages yellowish, A1, A2,

A3, MP1 and LP1 piceous apically; last abdominal tergum paler than rest of body terga; legs and urogomphusdark yellow.

Head. Maxilla. Microspinulae lacking along inner margin of stipes.Thorax. Legs. Spinulae well developed along anteroventral margin of profemur, tibiae and tarsi; dorsal

secondary setae of metacoxa predominantly short; metafemoral natatory setae covering less than distal 1/2 ofdorsal margin.


temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith minute secondary setae along inner margin; dorsal surface of last abdominal segment covered with bothspine-like and hair-like secondary setae (cf. Fig. 84); urogomphus with secondary setae along both inner andouter margins, outer margin with elongate and hair-like setae only, except for one short spine-like setaproximally (cf. Fig. 85).


Third-instar larva (n = 1) (Figs 81–85)As second-instar larva except as follows:Colour. Body predominantly dark yellow to pale brown; head capsule (Fig. 81) dark brown, yellowish

around ocularia and over occipital region; frontoclypeus and parietale with diffuse reticulate brownishmaculae mesodorsally; body terga with a variable number of small yellowish maculae; legs and urogomphusdark yellow to pale brown.

Thorax. Legs (Figs 82–83). Metafemoral natatory setae present along less than 1/2 of dorsal margin.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 7 and Figs 82–83;


Remarks. Rhantus exsoletus is a Palearctic species, which can be grouped with those species characterized bythe presence of elongate and hair-like setae and one short spine-like seta along outer margin of urogomphus(Fig. 85) (R. consputus; R. validus, R. simulans, R. wallisi, R. suturellus, R. suturalis, R. latitans, R.notaticollis, R. fennicus). Compared to the other Palearctic species studied (i.e., R. consputus, R. latitans, R.notaticollis, R. fennicus, R. suturellus, R. suturalis), larvae of R. exsoletus are characterized by the followingcombination of characters: longer antenna compared to length of maxillary palpus, shorter length of LAScompared to HW and longer urogomphus compared to HW (Tables 9–11), presence of microspinulae alonginner margin of stipes (second and third instar), number of natatory setae on metatibia (Tables 5, 7) (secondand third instar), presence of one additional seta along inner margin of stipes (first instar) and urogomphusfractured proximally (second and third instar) (Fig. 85), presence of at least two secondary setae onprotrochanter and presence of PV secondary setae on tarsi (Tables 7, 8).

Larvae of this species were previously described by Meinert (1901), Bertrand (1928) and Galewski(1963).



Description of larvae of Rhantus fennicus Huldén, 1982

Source of material. The larvae studied were collected by A.N. Nilsson in association with adults at thefollowing locality: Sweden, Västerbotten province, Märdsele, river fen 21.VI.1986.

First-instar larva (n = 1) (Figs 86–90)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Body predominantly pale brown; head capsule yellowish, pale brown mesally; head appendages,

legs and urogomphus testaceous.Head. Head capsule (Fig. 86). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulae

over dorsal surface; adnasaliae converging inward; occipital carina well defined; parietale distinctlyconstricted at level of occipital region, with microspinulae covering basal 1/3 of dorsal surface. Antenna.Microspinulae lacking, antennomere III with a ventroapical spinula. Maxilla. Palpus lacking microspinulae.Labium. Palpus lacking microspinulae.

Thorax. Legs (Figs 87–88). Microspinulae reduced, present over dorsal margin of coxae and ventralmargin of femora; tarsal claws with microspinulae over basal 1/3 to 1/2 of ventral margin.


present (Fig. 86); anterior margin of frontoclypeus with 24 spatulate lamellae clypeales; A3 with twoadditional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorter than palpiferand galea; stipes lacking additional setae along inner margin; anterodorsal primary setae of prementumminute; procoxal seta CO7 articulated proximally to articulation of seta CO6; meso- and metafemoral setaFE5 elongate and hair-like (Fig. 88); seta TI7 elongate and hair-like (Fig. 88); urogomphus (Fig. 90) with oneadditional seta; primary seta UR2 about as long as seta UR3; primary seta UR4 about as long as any of setaeUR5, UR6 or UR8; seta UR5 articulated posterior to articulation of seta UR7; seta UR7 shorter than any ofsetae UR5, UR6 or UR8.

Second-instar larva (n = 1)As first-instar larva except as follows: Head. Maxilla. Microspinulae lacking along inner margin of stipes.Thorax. Legs. Anteroventral spinulae well developed on profemur, tibiae and tarsi; metacoxa with

elongate hair-like secondary setae along dorsal margin; metafemoral natatory setae along distal 1/2 of dorsalmargin.


temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith minute secondary setae along inner margin; dorsal surface of last abdominal segment covered with bothspine-like and hair-like secondary setae (cf. Fig. 94); urogomphus with elongate and hair-like secondary setaeonly, except for one short spine-like secondary seta proximally on outer margin (cf. Fig. 95).


Third-instar larva (n = 1) (Figs 91–95)As second-instar larva except as follows:Colour. Head capsule (Fig. 91) with an irrorate colour pattern; thoracic terga with variable number of

testaceous maculae; legs and urogomphus dark yellow to pale brown.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 7 and Figs 92–93;




Remarks. Rhantus fennicus is a Palearctic species, which belongs to the group of species characterized by thepresence of elongate and hair-like natatory setae and one shorter spine-like seta along the outer margin ofurogomphus (Fig. 95) (R. consputus, R. validus, R. simulans, R. wallisi, R. suturalis, R. suturellus, R. latitans,R. notaticollis, R. exsoletus). Compared to the other Palearctic species studied (i.e., R. consputus, R. latitans,R. notaticollis, R.exsoletus, R. suturellus, R. suturalis), larvae of R. fennicus can be recognized by thefollowing combination of characters: shorter maxillary palpus compared to length of labial palpus and lengthof urogomphus compared to HW (Tables 9–11), microspinulae lacking along inner margin of stipes, numberof natatory setae on metatibia (second and third instar) (Tables 5, 7), procoxal seta CO7 articulatedproximally, anterior to seta CO6 (first instar), presence of at least 2 ventral additional setae on tarsi (firstinstar) (Figs 87–88) (Table 4), and urogomphus fractured proximally (second and third instar) (Fig. 95),presence of at least two secondary setae on protrochanter and presence of PV secondary setae on tarsi (Tables7, 8).

Larvae of this species were previously described by Nilsson (1987).

Description of larvae of Rhantus frontalis (Marsham, 1802)

Source of material. The larvae studied were collected in association with adults by A.N. Nilsson at thefollowing locality: Sweden, Närke province, Lake Kvismaren, 1.VI.1982.

First-instar larvaNo specimens available for study.

Second-instar larva (n = 1)Measurements and ratios aimed to characterize body shape shown in Table 10.Colour. Body predominantly brown; head capsule with few yellowish maculae.Head. Maxilla. Microspinulae present along inner margin of stipes.Thorax. Legs. Anteroventral spinulae strongly developed on profemur, tibiae and tarsi; metacoxa with

short secondary setae along dorsal margin; metafemoral natatory setae along distal 1/2 of dorsal margin.Abdomen. Urogomphus. Fractured proximally (cf. Fig. 100).Chaetotaxy. Number and position of secondary setae on legs are shown in Table 5; parietale with 9–11


Third-instar larva (n = 1) (Figs 96–100)As second-instar larva except as follows:Colour. Head capsule with an irrorate colour pattern (Fig. 96).Chaetotaxy. Number and position of secondary setae on legs are shown in Table 7 and 97–98; parietale

with 10 temporal spine-like setae.Measurements and ratios aimed to characterize body shape shown in Table 11.

Remarks. Rhantus frontalis groups with those species characterized by the presence of a variable number ofboth elongate hair-like and short spine-like secondary setae along the outer margin of urogomphus (i.e., R.signatus, R anisonychus, R. capensis, R. binotatus, R. calileguai, R. socialis, R. phocaenarum). Among these,R. frontalis is the only species found in the Palearctic region.



Description of larvae of Rhantus grapii (Gyllenhal, 1808)

Source of material. The larvae studied were collected by A.N. Nilsson in association with adults at thefollowing locality: Sweden, Gotland province, Rute and Storugns, smaller wetlands, 2.VII.1996.

First-instar larva (n = 1) (Figs 101–106)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Body predominantly creamy white to pale yellow.Head. Head capsule (Fig. 101). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulae

over dorsal surface; adnasaliae diverging outward; occipital carina lightly impressed, almost lacking; parietalenot constricted at level of occipital region, with microspinulae at most over posterior 1/2 of dorsal surface.Antenna. Microspinulae present over most of dorsal surface, A3 lacking a ventroapical spinula. Maxilla (Fig.102). Palpus with microspinulae over most of dorsal surface. Labium. Palpus with microspinulae over most ofdorsal surface.

Thorax. Legs (Figs 103–104). Microspinulae present over most of anterior surface; tarsal claws withmicrospinulae over basal 1/2 of ventral margin.

Abdomen. Urogomphus (Fig.106). Microspinulae present over most of dorsal surface.Chaetotaxy. Position and number of additional setae on legs are shown in Table 4; primary pore FRe

present (Fig. 101); anterior margin of frontoclypeus with 28 spine-like lamellae clypeales; A3 with twoadditional ventroapical pores; primary seta MX7 slightly longer than galea (Fig. 102); primary seta MX5longer than palpifer and galea (Fig. 102); stipes lacking additional setae along inner margin (Fig. 102);anterodorsal primary setae of prementum elongate; procoxal seta CO7 articulated proximally to articulation ofseta CO6; meso- and metafemoral seta FE5 elongate and hair-like (Fig. 104); seta TI7 elongate and hair-like(Fig. 104); urogomphus (Fig. 106) with one additional seta; primary seta UR2 longer than seta UR3; primaryseta UR4 about as long as any of setae UR5, UR6 or UR8; seta UR5 articulated posterior to articulation of setaUR7; seta UR7 shorter than any of setae UR5, UR6 or UR8.

Second-instar larva (n = 2)As first-instar larva except as follows:Colour. Body predominantly brownish; head appendages paler; tergum of abdominal segments VII and

VIII slightly paler than rest of body; legs dark brown except distal 1/2 of procoxa creamy white; urogomphuspale brown.

Head. Maxilla. Microspinulae lacking along inner margin of stipes.Thorax. Legs. Anteroventral spinulae weakly developed or lacking; dorsal setae of metacoxa

predominantly elongate; metafemoral natatory setae covering distal 2/3 of dorsal margin.Abdomen. Urogomphus. Not fractured proximally (cf. Fig. 111).Chaetotaxy. Number and position of secondary setae on legs are shown in Table 5; parietale with 3–6

temporal spine-like setae, most anterior ones articulated at about level of occipital region; stipes with minutesecondary setae along inner margin; dorsal surface of last abdominal segment covered with both spine-likeand hair-like secondary setae (cf. Fig. 110); urogomphus with secondary setae along both inner and outermargins, outer margin with elongate and hair-like setae only, lacking short spine-like setae (cf. Fig. 111).


Third-instar larva (n = 2) (Figs 107–111)As second-instar larva except as follows:Colour. Tibiae and tarsi yellowish; last abdominal segment pale brown; urogomphus either yellow or

brown.Thorax. Legs (Figs 108–109). Metafemoral natatory setae present along distal 3/4 of dorsal margin.



Chaetotaxy. Number and position of secondary setae on legs are shown in Table 7 and Figs 108–109;parietale with 6–7 temporal spine-like setae.


Remarks. Larvae of Rhantus grapii are characterized by several unique features within Rhantus: occipitalcarina lightly impressed (first instar) (Fig. 101), parietale not constricted at level of occipital region (firstinstar) (Fig. 101), adnasaliae diverging outwards (Fig. 101), A3 lacking a ventroapical spinula (first instar),primary setae MX5 and MX7 elongate, longer than galea (first instar) (Fig. 102), femora with at least oneadditional seta along dorsal margin (first instar) (Fig. 103), primary seta UR2 longer than seta UR3 (firstinstar) (Fig. 106), most anterior temporal spine-like setae articulated at level of occipital region (second- andthird instar) (Fig. 107), galea elongate (Fig. 102) (cf. ratio GA/MP1, Tables 9–11), and a reduced number ofnatatory setae on tibiae (second and third instar) (Fig. 109) (Tables 5, 7).

All larval instars of this species were previously described by Bertrand (1928) and Galewski (1963).

Description of larvae of Rhantus latitans Sharp, 1882

Source of material. The single third-instar larva studied was collected by M. Hess in association with adultsat the following locality: Germany, Bavaria, Deggendorf, 16.VIII.1993.

First- and second-instar larvaeNo specimens available for study.

Third-instar larva (n = 1) (Figs 112–116)Measurements and ratios aimed to characterize body shape shown in Table 11.Colour. Body predominantly dark yellow to pale brown; head capsule (Fig. 112) dark yellow with a dark

brown reticulate pattern mesally over frontoclypeus and parietale; head appendages yellow, A1, A2, A3, MP1,MP2, MP3, LP1 and LP2 infuscate apically; body terga predominantly dark yellow to pale brown; thoracicand abdominal terga I to VI infuscate mesally, segments VII and VIII brown; legs yellowish; urogomphusyellow proximally, brownish distally.


metacoxa with dorsal secondary setae predominantly short; metafemoral natatory setae present along distal 1/3 of dorsal margin.

Abdomen. Urogomphus (Fig. 116). Not fractured proximally.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 8 and Figs 113–114;

parietale with 10 temporal spine-like setae, most anterior ones articulated at about level of posterior margin ofocularium; stipes with minute secondary setae along inner margin; dorsal surface of last abdominal segmentcovered with both spine-like and hair-like secondary setae (Fig. 115); urogomphus with secondary setae alongboth inner and outer margins, outer margin with elongate hair-like setae only, except for one short spine-likeseta proximally (Fig. 116).

Remarks. Rhantus latitans is a Palearctic species, which belongs to the group of species characterized bythe presence of elongate and hair-like natatory setae and one short spine-like seta along outer margin ofurogomphus (Fig. 116) (R. consputus; R. validus, R. simulans, R. wallisi, R. suturellus, R. suturalis, R.fennicus, R. notaticollis, R.exsoletus). Compared to other similar Palearctic species (i.e., R. consputus, R.fennicus, R. notaticollis, R. exsoletus, R. suturellus, R. suturalis), third-instar larvae of R. latitans are readilyrecognized by the following combination of characters: absence of microspinulae along inner margin ofstipes, dorsal secondary setae of metacoxae predominantly short, longer LAS and shorter urogomphus



compared to HW (Table 11), and urogomphus not fractured proximally (Fig. 116); presence of at least twosecondary setae on protrochanter and presence of PV secondary setae on tarsi (Tables 7, 8).

Larvae of this species were described previously by Galewski (1963).

Description of larvae of Rhantus notaticollis (Aubé, 1837)

Source of material. The larvae studied were collected by S. Kholin in association with adults at the followinglocality: Russia, Sakhalin island, Kostromskoye village, temporary pond, 24.VI and 8.IX.1993.

First-instar larva (n = 1) (Figs 117–121)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Body predominantly dark brown. Head. Head capsule (Fig. 117). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulae

over dorsal surface; adnasaliae converging inward; occipital carina well defined; parietale distinctlyconstricted at level of occipital region, with microspinulae covering whole dorsal surface. Antenna.Microspinulae lacking, antennomere III with a ventroapical spinula. Maxilla. Palpus lacking microspinulae.Labium. Palpus lacking microspinulae.

Thorax. Legs (Figs 118–119). Microspinulae present over most of anterior surface; tarsal claws withmicrospinulae over basal 1/2 of ventral margin.


present (Fig. 117); anterior margin of frontoclypeus with 20 digitiform lamellae clypeales; A3 with twoadditional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorter than palpiferand galea; stipes lacking additional setae along inner margin; anterodorsal primary setae of prementumminute; procoxal seta CO7 articulated distally, at about level of articulation of seta CO6; meso- andmetafemoral seta FE5 elongate and hair-like (Fig. 119); seta TI7 elongate and hair-like (Fig. 119);urogomphus (Fig. 121) with one additional seta; primary seta UR2 about as long as seta UR3; primary setaUR4 about as long as any of setae UR5, UR6 or UR8; seta UR5 articulated posterior to articulation of setaUR7; seta UR7 shorter than any of setae UR5, UR6 or UR8.

Second-instar larva (n = 1)As first-instar larva except as follows:Head. Maxilla. Microspinulae present along inner margin of stipes.Thorax. Legs. Anteroventral spinulae well developed on profemur, tibiae and tarsi; metacoxa with

predominantly short secondary setae along dorsal margin; metafemoral natatory setae along distal 1/2 ofdorsal margin.


temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith minute secondary setae along inner margin; dorsal surface of last abdominal segment covered with bothspine-like and hair-like secondary setae (cf. Fig. 125); urogomphus with secondary setae along both inner andouter margins, outer margin with elongate and hair-like setae only, except for one short spine-like setaproximally (cf. Fig. 126).

Measurements and ratios aimed to characterize body shape shown in Table 10.Third-instar larva (n =2) (Figs 122–126)

As second-instar larva except as follows:Colour. Antenna and urogomphus paler.Thorax. Legs (Figs 123–124). Metafemoral natatory setae present along distal 3/4 of dorsal margin.



Chaetotaxy. Number and position of secondary setae on legs are shown in Table 8 and Figs 123–124;parietale with 9 temporal spine-like setae.


Remarks. Rhantus notaticollis is a Palearctic species, which belongs to the group of speciescharacterized by the presence of elongate and hair-like natatory setae and one short spine-like seta along outermargin of urogomphus (Fig. 126) (R. consputus; R. validus, R. simulans, R. wallisi, R. suturellus, R. suturalis,R. fennicus, R. latitans, R.exsoletus). Compared to other similar Palearctic species (i.e., R. consputus, R.fennicus, R.latitans, R. exsoletus, R. suturellus, R. suturalis), larvae of R. notaticollis can be distinguished bythe following combination of characters: absence of microspinulae along inner margin of stipes, dorsalsecondary setae on metacoxa predominantly elongate (best seen in third instar), number of natatory setae onmetatibia (second and third instar) (Tables 5, 8), shorter LAS and urogomphus compared to HW (Tables 9–11), presence of microspinulae over most of dorsal surface of frontoclypeus and urogomphus (first instar),presence of at least two secondary setae on protrochanter and presence of PV secondary setae on tarsi (Tables7, 8).

All instars of R. notaticollis were previously described by Galewski (1963).

TABLE 8. Number of secondary setae1 on the legs of instar III of selected species of Rhantus Dejean (acronyms as inTable 1). A = anterior, AD = anterodorsal, AV = anteroventral, CO = coxa, D = dorsal, Di = distal, FE = femur, NS =natatory setae, PD = posterodorsal, PV = posteroventral, Pr = proximal, TA = tarsus, TI = tibia, TR = trochanter, V =

ventral, n = number of specimens studied, Total = total number of secondary setae on segment.

Segment Sensillar

series

LAT

(n = 1)2

MON3

(n = 1)

NOT

(n = 2)

ORB

(n = 1)2

PHO

(n = 2)

POE3

(n = 1)2

SIG

(n = 3)

SIM

(n = 2)

SOC

(n = 3)

SUT

(n = 3)

VAL

(n = 1)2

WAL

(n = 3)ProCO D(NS) 13 23–25 13 11 14–17 27 7–14 13–16 14–18 13–15 21–23 12–17

A 7–9 18 8 14 9 15–16 6–9 7–9 10–13 6–9 19–21 8–10V 4 1 2–4 1 4–5 0 2–4 4 4–6 3–6 4–7 5–7Total 24–26 42–43 25–23 26 27–31 42–43 16–26 26–27 30–35 23–28 47–48 27–31

ProTR Pr 3–5 6–7 2–3 0 3–5 5 2–3 1 2 2–3 6–7 2–4Di 0 4 1 0 0 1–3 0 0 0 0 0–1 0Total 3–5 10–11 3–4 0 3–5 6–8 2–3 1 2 2–3 7 2–4

ProFE NS (PD) 27–28 20–21 30–32 38–41 29–36 31 23–25 30–41 33–38 25–28 29–31 31–36AD 8–11 34–36 10–13 10–11 6–11 28 8–11 8–11 10–16 11–14 16–19 13–15AV 23–27 32–36 18–21 7 21–24 24–27 11–13 15–17 11–13 14–23 20–21 15–25PD 0 10 0 0 0 1 0 0 0 0 0 0PV 9 24–26 9–11 9 9–10 14–15 8–11 8–11 9–11 10–13 11–13 9–11Total 68–74 123–126 72 65–67 69–77 99–101 52–57 63–78 65–74 68–72 80 68–85

ProTI NS (PD) 27–28 23–25 25–26 28–30 25–28 29–30 22–24 29–32 26–30 24–28 24–25 25–29AD 4 19–22 2–3 1 3–4 12–14 2–4 3 2–4 3–4 4–5 3–4AV 5–8 9–11 5–6 4 6–7 7–11 3–5 4–6 4–6 6–7 5–6 5–6PD 0 1–5 0 0 0 1 0 0 0 0 0 0PV 3–5 11–12 4–5 2 3–4 8 3–5 3–4 2 3–5 8 3–5Total 41–43 64–74 37–39 35–37 38–42 59–62 31–36 42 36–41 37–43 41–43 39–42

ProTA NS (PD) 20–24 15–17 21 18 20–21 19–20 16–19 17–23 20–23 19–21 19–22 23–25AD 2 10–14 2–3 0 2 8 1–2 2 2 2 4 2AV 4–6 11–14 5 4 5–7 11 4–5 3–5 5 4–6 5 5–6PD 0 4–5 0 0 0 0 0 0 0 0 0 0PV 3–4 9–11 3 0 0 9 0 0 0 2–3 5–6 4Total 31–34 52–58 31 22 28–29 47–48 21–26 22–30 27–30 27–35 34–36 34–37

MesoCO D(NS) 11–12 25–26 13–16 8–13 15 30 7–12 12–15 11–13 12–15 20–25 11–20A 8–10 22 8–10 11–13 12 21 6–9 10–12 8–13 8–9 20–22 10–12V 4–5 0–1 3–4 3–4 5–6 0 3–6 5 7–8 4–6 7–8 5–6Total 23–27 48 24–30 23–29 32–33 51 16–26 27–31 28–31 27–28 51–56 26–38

MesoTR Pr 3 10 3–5 2 4–6 7 1–4 1–2 3–5 3–5 8–10 3–5Di 0 3 0–1 0 0 1–2 0 0 0–1 0 0–1 0Total 3 13 3–6 2 4–6 8–9 1–4 1–2 3–6 3–5 9–10 3–5

MesoFE NS (PD) 22–24 20–21 24–30 36 24–36 24–27 20–24 29–35 32–39 19–27 23–30 29–32AD 15 32–43 11–15 9–10 16 20–27 9–12 9 12–22 12–14 20–22 14–15AV 17–19 26–30 19–21 13–15 13–14 14–19 12–14 14–15 10–15 19–20 18–20 17–20PD 0 1–10 0 0 0 0–1 0 0 0 0 0 0PV 13–14 33–34 12–17 10–13 11–12 15–19 11–13 10–13 11–14 13–14 12 12–14Total 69–70 123–127 72–77 70–72 66–76 73–93 55–60 63–71 65–76 65–73 73–82 74–80

continued next page



1 including additional setae, cf. material and methods; 2 both legs of a single specimen included; 3 Balke et al. (2007).

Description of larvae of Rhantus orbignyi Balke, 1992

Source of material. The larvae studied were collected by M. Archangelsky and M.C. Michat at the followinglocalities: Argentina: Magdalena, Buenos Aires Province, 23.VI.2001 (stream with floating vegetation);Buenos Aires City, 25.IX.2000 (big permanent pond with littoral vegetation), 11.VI.2001 (pond about 30 mlong with abundant vegetation), IX.2004 (temporary rain pool). They were identified by size and elimination.Two species of Rhantus are historically present in Buenos Aires city and nearby areas: R. signatus, which isvery common, and R. orbignyi, which is rare. These larvae are bigger in size than those of R. signatus, andclearly differ in their external appearance. Adults of R. orbignyi are bigger in size than those of R. signatus(Trémouilles 1984).

First-instar larva (n = 3) (Figs 127–131)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Dorsal surface of head dark brown except for a light brown macula enclosing each egg burster;

head appendages brown except for MN dark brown; thoracic and abdominal tergites, legs and urogomphusbrown.

Head. Head capsule (Fig. 127). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulaeover dorsal surface; adnasaliae converging inward; occipital carina well defined; parietale distinctlyconstricted at level of occipital region, with microspinulae covering posterior 1/2 of dorsal surface. Antenna.

TABLE 8. (continued)Segment Sensillar

series

LAT

(n = 1)2

MON3

(n = 1)

NOT

(n = 2)

ORB

(n = 1)2

PHO

(n = 2)

POE3

(n = 1)2

SIG

(n = 3)

SIM

(n = 2)

SOC

(n = 3)

SUT

(n = 3)

VAL

(n = 1)2

WAL

(n = 3)MesoTI NS (PD) 35 30 28–31 33 30–39 31–34 24–29 31–36 30–34 26–32 27–29 31–35

AD 7 23–24 4–5 1–2 6–9 16–17 4–6 5 4–8 4–7 7–8 7–8AV 11 14–18 9–12 5–7 9–10 12–14 7–9 9 5–8 6–9 9–11 8–9PD 0 5–7 0 0 0 0–1 0 0 0 0 0–2 0PV 5–6 9–13 4–5 2–3 5–6 6–12 2–4 4 3–5 5 8 5–6Total 58–59 85–88 45–53 41–45 50–64 67–76 38–46 49–54 46–52 42–53 51–56 52–56

MesoTA NS (PD) 26–30 28–29 27–28 23–24 26–33 29–30 20–26 22–32 29–33 24–30 29 29–34AD 2–3 19–20 2 1 2–3 16–18 2 2 3–4 2 7 2AV 9–10 12–15 7–8 6 9–10 13–14 5–9 7–8 6–8 8–10 8–9 7–9PD 0 2 0 0 0 1–2 0 0 0 0 0 0PV 5 12–15 4–5 0 2–3 9–12 1–2 0 3 3–6 7–8 4–6Total 42–48 74–80 41–42 31–31 40–48 69–75 29–36 32–41 42–47 38–48 52 44–49

MetaCO D(NS) 10–12 15–19 13–14 10 13 17–20 6–10 10–13 7–9 11–13 18–22 10–16A 9–13 20–21 9–12 17 6–10 24 6–12 6–15 11–15 10–11 26–28 11–17V 3–4 0–1 3 2–3 4–5 0 3–6 2–5 4–6 2–5 6–7 4–5Total 23–28 36–40 25–29 29–30 23–28 41–44 20–24 18–33 22–28 24–29 51–56 30–37

MetaTR Pr 4–5 9–10 3–6 3 5–8 7–9 2–4 2 5–6 4–5 7–8 4–5Di 0 3–4 0–1 1 0–1 1 0 0 0 0 1–2 0Total 4–5 12–14 3–7 4 5–9 8–10 2–4 2 5–6 4–5 9 4–5

MetaFE NS (PD) 8–9 9–10 10–11 11–12 10–17 18–23 6–8 10–13 16–25 6–9 6 12–15AD 15–16 40–43 15–16 11 17–23 23–30 11–14 8–12 12–16 16–19 26–27 17–19AV 14–17 23–26 13–19 11 12–13 12–20 10–12 12–15 14–16 14–19 19–21 15–17PD 0 4–10 0 0 0 0 0 0 0 0 0 0PV 13–16 26–28 9–16 10 12–14 16 9–11 7 15 11–15 9–10 7–14Total 53–55 107–112 54–55 43–44 58–60 74–84 39–41 40–44 57–71 50–58 60–64 54–62

MetaTI NS (PD) 34–35 37–38 30–31 36 38–42 33–39 25–31 31–32 33–37 24–28 25–29 31–33AD 9–11 25–31 7–9 3–4 8–11 16–19 5–9 5–7 6–11 7–11 12 7–10AV 10–11 15–17 8 7–9 11–13 12–14 7–9 9–10 6–9 9–12 8–11 9–10PD 0 0–5 0 0 0 0–1 0 0 0 0 0–2 0PV 5 13–16 4 0–1 5–8 9–12 3–5 3 4–5 5–6 9 4–6Total 59–61 98–99 49–52 46–50 62–74 75–80 42–50 49–51 52–61 47–56 58–59 52–59

MetaTA NS (PD) 35–37 37–39 30–33 34–35 36–38 33–38 25–29 29–36 33–35 24–35 33–36 33–38AD 4 20–21 2 1 4 14–17 2–3 2–3 4–5 2–4 7–8 2–4AV 10 14 9–10 9 10 10–11 7–10 8–9 6–9 8–13 9–10 9–11PD 0 0–1 0 0 0 0 0 0 0 0 0 0PV 4–5 13 5 0 3–5 7–10 1–2 0 2–5 4–6 7–8 4–5Total 54–55 85–87 46–50 44–45 53–57 64–76 37–41 40–47 45–52 39–58 58–60 49–57



Microspinulae lacking, antennomere III with a ventroapical spinula. Maxilla. Palpus lacking microspinulae.Labium. Palpus lacking microspinulae.

Thorax. Legs (Figs 128–129). Microspinulae reduced to dorsal margin of coxae and ventral margin offemora, tibiae and tarsi; tarsal claws with microspinulae over basal 1/2 of ventral margin.

Abdomen. Urogomphus (Fig. 131). Microspinulae present over basal 1/2.Chaetotaxy. Position and number of additional setae on legs are shown in Table 4; primary pore FRe

absent (Fig. 127); anterior margin of frontoclypeus with 15–16 digitiform lamellae clypeales; A3 with twoadditional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorter than palpiferand galea; stipes lacking additional setae along inner margin; anterodorsal primary setae of prementumminute; procoxal seta CO7 articulated distally, at about level of articulation of seta CO6; meso- andmetafemoral seta FE5 short and spine-like (Fig. 129); seta TI7 short and spine-like (Fig. 129); urogomphus(Fig. 131) with one additional seta; primary seta UR2 about as long as seta UR3; primary seta UR4 about aslong as any of setae UR5, UR6 or UR8; seta UR5 articulated posterior to articulation of seta UR7; seta UR7shorter than any of setae UR5, UR6 or UR8.

Second-instar larva (n = 3)As first-instar larva except as follows:Colour. Surface of head dark brown dorsally and ventrally, except for a dorsal yellowish macula posterior

to each lateral margin of frontoclypeus; head appendages brown; thoracic and abdominal sclerites brown todark brown, membranous parts brownish testaceous to light brown; legs brown; urogomphus dark yellow tolight brown.

Head. Maxilla. Microspinulae present along inner margin of stipes.Thorax. Legs. Ventral marginal spinulae well developed on profemur, tibiae and tarsi; metacoxa with

predominantly elongate hair-like secondary setae along dorsal margin; metafemoral natatory setae along distal3/4 of dorsal margin.


temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith minute secondary setae along inner margin; dorsal surface of last abdominal segment covered with bothspine-like and hair-like secondary setae (cf. Fig. 135); urogomphus lacking secondary setae (cf. Fig. 136).


Third-instar larva (n = 3) (Figs 132–136)As second-instar larva except as follows:Colour. Surface of head dark brown to dark ferrugineous dorsally (Fig. 132); head appendages brown

except for MN dark brown; thoracic tergites pale black to dark ferrugineous; abdominal tergites I–VI darkbrown to pale black, sclerites VII and VIII brown; membranous parts testaceous to brownish; legs brown todark brown; urogomphus yellow to pale brown, distal portion dark.

Thorax. Legs (Figs 133–134). Metafemoral natatory setae present along distal 3/4 of dorsal margin.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 8 and Figs 133–134;

parietale with 7 temporal spine-like setae.Measurements and ratios aimed to characterize body shape shown in Table 11.

Remarks. Larvae of R. orbignyi are likely to be confounded with those of R. calidus and R. antarcticusnahueli (see under R. antarcticus nahueli) owing to the absence of secondary setae on urogomphus.Compared to these species, R. orbignyi can be easily recognized by the following combination of features:size, relative elongation of A4 compared to A3, longer antenna compared to length of maxillary palpus



(Tables 9–11), presence of microspinulae along inner margin of stipes, number of natatory setae on metatibia(second and third instar) (Tables 6, 8) (see also under R. calidus and R. antarcticus nahueli).

The third-instar larva of R. orbignyi was previously described by Crespo (1987).

TABLE 9. Measurements and ratios for the instar I of selected species of Rhantus (acronyms as in Table 1); l, length; w,width; ?, missing data.

TABLE 9. Continuation.

Description of larvae of Rhantus phocaenarum Guignot, 1957

Source of material. The larvae studied were collected in association with adults by L. Hendrich at thefollowing localities. La Réunion, Fundarte, Cilias, 1200 m, 26–30.XII.1998; SE St-Paul, SE Petite France,

MeasureANI(n = 3)

ANT(n = 6)

BIN(n = 2)

CAL(n = 1)

CAG(n = 6)

CON(n = 1)

EXS(n = 2)

FEN(n = 1)

GRA(n = 1)

HL (mm) 0.88–1.00 1.32–1.39 0.90–0.91 0.88 0.87–0.99 1.20 1.15–1.17 1.10 1.09HW (mm) 0.87–0.92 1.34–1.44 0.86–0.87 1.06 0.86–0.89 1.09 1.03–1.05 1.01 1.01FRL (mm) 0.42–0.45 0.62–0.67 0.43–0.44 0.44 0.43–0.47 0.51 0.47–0.50 0.50 0.58OCW (mm) 0.47–0.48 0.76–0.88 0.45–0.46 0.53 0.42–0.47 ? 0.41–0.44 0.53 0.56HL/HW 1.01–1.09 0.94–1.04 1.04–1.05 0.88 1.01–1.11 1.10 1.09–1.13 1.12 1.08HW/OCW 1.83–1.96 1.64–1.76 1.91–1.93 2.02 1.82–2.12 ? 2.35–2.55 1.92 1.79A/HW 0.86–0.93 0.65–0.70 0.99–1.00 1.06 0.82–0.94 1.13 1.35–1.37 1.08 1.00A4/A1 1.41–1.50 1.72* 1.49–1.51 1.07 1.33–1.73 1.42 1.53–1.66 1.87 1.78A4/A3 1.14–1.17 1.22–1.31 1.14–1.15 0.83 0.95–1.12 0.96 1.16–1.22 1.24 1.55MN(l/w) 2.48–2.62 2.67–2.85 2.44–2.45 2.56 2.38–2.73 2.65 2.43–2.53 3.00 2.84A/MP 1.34–1.46 1.41–1.53 1.50–1.51 1.40 1.37–1.55 1.66 1.66–1.67 1.30 1.70MP3/MP2 1.22–1.31 1.27–1.35 1.17–1.19 1.05 1.11–1.22 1.16 1.16–1.18 1.16 1.60GA/MP1 0.48–0.55 0.60–0.70 0.49–0.50 0.43 0.47–0.57 0.48 0.47–0.48 0.50 1.28MP/LP 1.19–1.23 0.94–0.99 1.19–1.21 1.20 1.09–1.25 1.09 1.07–1.13 1.18 1.05LP2/LP1 1.14–1.22 1.07–1.15 0.92–1.00 1.04 1.00–1.34 1.06 1.01–1.04 1.18 0.85L3 (mm) 2.61–2.79 3.99–4.16 2.69–2.73 2.69 2.62–2.88 3.16 3.45–3.60 3.22 2.89L3/HW 3.00–3.06 2.89–2.99 3.12–3.13 2.54 3.00–3.29 2.91 3.35–3.43 3.19 2.86LAS (mm) 0.57–0.70 0.82–0.84 0.60–0.62 0.97 0.51–0.57 0.97 0.87–0.88 0.91 1.00LAS/HW 0.66–0.76 0.58–0.61 0.70–0.71 0.92 0.59–0.64 0.89 0.83–0.86 0.90 0.99U (mm) 1.26–1.31 1.54–1.78 1.34–1.36 0.84 1.33–1.62 1.49 1.82–1.83 1.47 1.00U/HW 1.37–1.47 1.15–1.29 1.55–1.56 0.80 1.49–1.87 1.37 1.75–1.77 1.45 0.99U/LAS 1.79–2.23 1.88–2.02 2.17–2.21 0.87 2.33–3.12 1.53 2.07–2.10 1.61 1.00

MeasureNOT(n = 1)

ORB(n = 3)

PHO(n = 1)

SIG(n = 5)

SOC(n = 3)

SUT(n = 2)

VAL(n = 2)

WAL(n = 2)

HL (mm) 0.99 1.08–1.16 0.99 0.85–0.92 0.87–0.91 1.07–1.14 1.40 1.12–1.13HW (mm) 0.95 1.02–1.07 0.95 0.78–0.89 0.79–0.85 1.08 1.26–1.28 1.04–1.05FRL (mm) 0.43 0.56 0.43 0.38–0.43 0.41–0.44 0.48–0.51 0.64–0.66 0.49–0.50OCW (mm) 0.42 0.51–0.52 0.55 0.37–0.43 0.41–0.44 0.46–0.52 0.62–0.66 0.46–0.49HL/HW 1.14 1.05–1.10 1.06 0.97–1.12 1.05–1.09 0.99–1.06 1.09–1.11 1.08–1.09HW/OCW 2.28 1.95–2.10 1.87 1.86–2.22 1.90–2.05 2.09–2.36 1.94–2.03 2.16–2.28A/HW 1.14 0.86–0.91 0.95 0.90–1.01 0.96–1.01 1.05–1.12 0.77 1.25–1.28A4/A1 1.59 1.61–1.80 1.23 1.43–1.78 1.33–1.38 1.66–1.74 1.48–1.49 1.62–1.66A4/A3 1.15 1.13–1.25 0.98 1.10–1.25 1.02–1.08 1.14–1.19 1.16–1.19 1.08–1.10MN(l/w) 2.67 2.58–2.95 2.55 2.11–2.55 2.51–2.69 2.44–2.58 2.77 2.35–2.40A/MP 1.58 1.63–1.70 1.44 1.38–1.48 1.40–1.42 1.56–1.59 1.27–1.29 1.73–1.76MP3/MP2 1.18 1.25–1.39 1.15 1.27–1.47 1.18–1.19 1.12–1.25 1.33–1.46 1.10–1.12GA/MP1 0.48 0.53–0.65 0.49 0.44–0.59 0.50–0.55 0.49–0.50 0.52–0.56 0.43MP/LP 1.01 1.04–1.08 1.17 1.08–1.16 1.18–1.26 0.99–1.01 1.13–1.15 1.00–1.05LP2/LP1 0.99 1.09–1.11 1.07 1.00–1.14 1.02–1.05 0.94–1.03 1.18–1.24 0.97–1.04L3 (mm) 2.95 3.13–3.31 3.17 2.38–2.64 2.56–2.61 3.04–3.13 3.61–3.75 3.21–3.23L3/HW 3.11 3.05–3.11 3.07 3.08–3.21 3.07–3.23 2.83–2.91 2.87–2.93 3.06–3.12LAS (mm) 0.82 0.67–0.98 0.69 0.56–0.62 0.52–0.53 0.92–0.94 0.78–0.82 0.87–0.90LAS/HW 0.87 0.66–0.92 0.67 0.63–0.78 0.62–0.66 0.86–0.88 0.62–0.64 0.82–0.83U (mm) 1.42 1.26–1.44 1.70 1.26–1.44 1.30–1.38 1.34–1.57 1.28–1.34 1.54–1.55U/HW 1.49 1.19–1.41 1.65 1.48–1.78 1.56–1.70 1.24–1.47 1.00–1.06 1.47–1.50U/LAS 1.72 1.34–2.15 2.46 2.10–2.53 2.47–2.62 1.45–1.67 1.56–1.72 1.73–1.77



1800 m, 22–25.XII.1998; NW LaPaline des palmists, Forêt de Bélouve, 1400 m, 3.I.1999. The association issafe as R. phocaenarum is the only species of Rhantus found in La Réunion.First-instar larva (n = 1) (Figs 137–141)

Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Body uniformly brown; head appendages brown except A1 creamy white; legs and urogomphus

brown.Head. Head capsule (Fig. 137). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulae

over most of dorsal surface except along anterior margin; adnasaliae converging inward; occipital carina welldefined; parietale distinctly constricted at level of occipital region, with microspinulae over most of dorsalsurface. Antenna. Microspinulae lacking, antennomere III with a ventroapical spinula. Maxilla. Palpus lackingmicrospinulae. Labium. Palpus lacking microspinulae.

Thorax. Legs (Figs 138–139). Microspinulae over most of anterior surface; tarsal claws withmicrospinulae covering basal 2/3 of ventral margin.

Abdomen. Urogomphus (Fig. 141). Microspinulae present over most surface.Chaetotaxy. Position and number of additional setae on legs are shown in Table 4; primary pore FRe

present (Fig. 137); anterior margin of frontoclypeus with 23 digitiform to spiniform lamellae clypeales; A3with two additional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorter thanpalpifer and galea; stipes lacking additional setae along inner margin; anterodorsal primary setae ofprementum minute; procoxal seta CO7 articulated distally, at about level of articulation of seta CO6; meso-and metafemoral seta FE5 elongate and hair-like (Fig. 139); seta TI7 elongate and hair-like (Fig. 139);urogomphus (Fig. 141) with one additional seta; primary seta UR2 about as long as seta UR3; primary setaUR4 shorter than any of setae UR5, UR6 or UR8; seta UR5 articulated posterior to articulation of seta UR7;seta UR7 shorter than any of setae UR5, UR6 or UR8.

Second-instar larva (n = 2)As first-instar larva except as follows:Colour. Paler.Head. Maxilla. Microspinulae lacking along inner margin of stipes.Thorax. Legs. Anteroventral spinulae weakly developed on profemur, well-developed on tibiae and tarsi;

metacoxa with predominantly short hair-like secondary setae along dorsal margin; metafemoral natatory setaepresent along distal 1/2 of dorsal margin.




Third-instar larva (n = 2) (Figs 142–146)As second-instar larva except as follows:Colour. Dorsal surface of head capsule with a variable number of yellowish maculae. Thorax. Legs (Figs 143–144). Metafemoral natatory setae present along distal 1/2 of dorsal margin.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 8 and Figs 143–144;


Remarks. Rhantus phocaenarum belongs to the group of species characterized by the presence of avariable number of elongate hair-like and short spine-like secondary setae along the outer margin of



urogomphus (Fig. 146) (i.e., R. signatus, R. frontalis, R. capensis, R. binotatus, R. calileguai, R. socialis, R.anisonychus). Compared to other African species included in this group (R. capensis and R. socialis) larvae ofR. phocaenarum are readily distinguished by the following combination of characters: absence ofmicrospinulae along inner margin of stipes (second and third instar), anteroventral spinulae of profemurreduced (second and third instar) (Fig. 143), number of natatory setae on metatibia (second- and third instar)(Tables 6, 8), relative elongation of LAS and urogomphus with respect to HW (Tables 9–11) and distalarticulation of procoxal seta CO7 (first instar).

TABLE 10. Measurements and ratios for the instar II of selected species of Rhantus (acronyms as in Table 1); l, length;w, width.


* from Alarie & Wang (2004)

MeasureANI(n = 2)

ANT(n = 6)

BIN(n = 2)

RCAL(n = 2)

CAG(n = 3)

CON(n = 1)

EXS(n = 2)

FEN (n = 1)

FOR* (n = 4)

HL (mm) 1.54–1.57 2.06–2.22 1.45–1.52 1.44–1.48 1.41–1.55 1.73 1.80–1.83 1.68 1.83–2.00

HW (mm) 1.50–1.54 2.14–2.20 1.43–1.45 1.60–1.63 1.34–1.46 1.70 1.63–1.64 1.59 1.86–1.98

FRL (mm) 0.68–0.69 0.92–0.98 0.66–0.63 0.68 0.62–0.67 0.72 0.74–0.75 0.73 0.80–0.82

OCW (mm) 0.83–0.85 1.16–1.22 0.85–0.94 0.79–0.84 0.72–0.84 0.90 0.80–0.83 0.80 0.92–1.02HL/HW 1.02–1.03 0.96–1.02 1.00–1.07 0.88–0.92 1.06 1.05 1.10–1.13 1.05 0.97–1.01HW/OCW 1.82–1.84 1.75–1.88 1.54–1.68 1.93–2.02 1.69–1.86 1.89 1.97–2.05 1.99 1.84–2.05A/HW 0.75–0.76 0.55–0.57 0.78–0.79 0.80–0.81 0.75–0.77 0.94 1.08–1.12 0.77 0.61–0.66A4/A1 1.14–1.15 1.11 1.02–1.04 0.71–0.73 1.06–1.21 1.00 1.23–1.28 1.35 0.90–0.97

A4/A3 0.92–0.95 1.16–1.17 0.87–0.93 0.70–0.74 0.87–0.98 0.75 1.02–1.07 1.06 0.90–0.97

MN(l/w) 2.88–3.00 2.42–2.64 2.53–2.68 2.88–3.09 2.78–3.00 2.60 2.66–2.68 3.03 2.61–2.63

A/MP 1.42–1.44 1.39–1.42 1.45–1.48 1.44–1.48 1.43–1.51 1.70 1.62–1.66 1.29 1.29–1.36

MP3/MP2 0.95–1.03 1.11–1.18 1.02–1.03 0.78–0.85 0.89–0.98 0.88 0.99–1.06 1.02 0.92–0.98

GA/MP1 0.37–0.39 0.56–0.61 0.44–0.49 0.34–0.43 0.29–0.44 0.49 0.43–0.44 0.43 0.40–0.44

MP/LP 1.25–1.30 0.96–1.02 1.14–1.15 1.19–1.21 1.17–1.23 1.13 1.07 1.20 1.34–1.43

LP2/LP1 0.98–1.04 0.88–0.93 0.91–0.92 0.83–0.89 0.82–0.92 0.79 1.10 0.94 0.89–0.96L3 (mm) 4.36–4.41 5.86–6.04 4.20–4.22 4.29–4.34 3.85–4.40 4.65 5.03–5.11 4.75 4.82–5.04L3/HW 2.83–2.94 2.71–2.77 2.91–2.95 2.67–2.68 2.87–3.00 2.74 3.07–3.14 2.99 2.55–2.64LAS (mm) 1.30–1.32 1.68–1.78 1.20–1.30 2.08–2.18 1.03–1.29 1.80 1.75–1.83 1.83 1.31–1.43LAS/HW 0.85–0.87 0.76–0.83 0.83–0.91 1.30–1.34 0.77–0.88 1.06 1.07–1.12 1.15 0.69–0.75

U (mm) 1.98–2.20 2.10–2.20 2.00–2.01 0.91–1.05 1.95–2.43 1.98 2.50–2.70 1.95 2.05–2.28

U/HW 1.28–1.47 0.95–0.99 1.38–1.41 0.57–0.65 1.45–1.67 1.16 1.54–1.65 1.23 1.08–1.16

U/LAS 1.52–1.69 1.19–1.25 1.54–1.67 0.44–0.48 1.85–2.00 1.10 1.37–1.54 1.07 1.44–1.67

MeasureFRO(n = 1)

GRA(n = 2)

NOT(n = 1)

ORB(n = 3)

PHO(n = 2)

SIG(n = 4)

SOC(n = 2)

SUT(n = 2)

VAL(n = 1)

WAL(n = 2)

HL (mm) 1.57 1.67 1.64 1.61–1.68 1.60–1.64 1.32–1.48 1.40–1.411.76–1.83 2.28 1.80–1.81

HW (mm) 1.55 1.48 1.58 1.59–1.64 1.55–1.63 1.25–1.32 1.35–1.41 1.73–1.75 2.06 1.68–1.69FRL (mm) 0.70 0.79–0.80 0.70 0.76–0.80 0.70–0.73 0.60–0.65 0.61–0.62 0.76–0.78 1.02 0.73–0.75OCW (mm) 0.88 0.90–0.93 0.78 0.96–1.12 0.76–0.85 0.66–0.70 0.69–0.73 0.80–0.90 1.10 0.85–0.88HL/HW 1.02 1.13 1.04 0.98–1.04 1.01–1.04 1.06–1.16 1.00–1.03 1.01–1.06 1.11 1.07–1.08HW/OCW 1.78 1.60–1.64 2.03 1.47–1.66 1.91–2.11 1.84–1.91 1.95 1.94–2.16 1.87 1.93–1.97A/HW 0.83 0.87–0.92 0.92 0.69–0.71 0.78–0.81 0.78–0.85 0.77–0.79 0.90–0.94 0.64 0.93–0.98A4/A1 1.11 1.27–1.36 1.37 1.28–1.31 0.97–1.02 1.13–1.24 1.00–1.04 1.18–1.33 0.97 1.20–1.22A4/A3 0.96 1.19–1.27 1.14 1.07–1.12 0.84–0.87 0.97–1.20 0.90–0.93 0.91–1.02 0.91 0.89–0.95MN(l/w) 2.63 2.80–2.83 2.56 2.46–2.71 2.67–2.79 2.58–2.68 2.67–2.82 2.41–2.70 2.81–3.00 2.53–2.73A/MP 1.57 1.64–1.85 1.64 1.58–1.61 1.41–1.46 1.43–1.53 1.43–1.48 1.57–1.58 1.32–1.35 1.65–1.66MP3/MP2 0.90 1.28–1.41 0.97 1.13–1.16 1.02–1.05 1.03–1.10 0.98–1.02 0.97–1.00 1.05–1.13 0.88–0.89GA/MP1 0.38 0.83–0.95 0.43 0.55–0.59 0.42–0.43 0.42–0.50 0.46–0.48 0.38–0.39 0.41–0.45 0.40–0.43MP/LP 1.13 1.00–1.05 0.99 1.08–1.09 1.20–1.22 1.10–1.15 1.18–1.23 1.02–1.03 1.24–1.30 0.98–1.03LP2/LP1 0.80 0.88–0.91 0.86 0.95 0.83–0.90 0.81–0.96 0.83–0.85 0.82–0.83 1.06 0.81–0.82L3 (mm) 4.82 4.43–4.60 4.49 4.59–4.66 4.70–4.72 3.87–4.15 3.92–3.97 4.65–4.80 5.98–6.06 4.69–4.74L3/HW 3.11 3.00–3.12 2.85 2.81–2.93 2.89–3.04 3.07–3.17 2.82–2.90 2.65–2.78 2.90–2.94 2.80–2.81LAS (mm) 1.60 2.00–2.03 1.63 1.56–1.59 1.08–1.10 1.10–1.26 0.89–0.95 1.70 1.70 1.70LAS/HW 1.03 1.36–1.37 1.03 0.96–0.99 0.66–0.71 0.88–0.96 0.66–0.67 0.97–0.99 0.83 1.01–1.02U (mm) 2.35 1.56–1.60 2.03 1.36–1.73 2.50–2.63 1.73–2.00 2.09–2.14 2.10–2.33 1.96–2.04 1.98–2.13U/HW 1.52 1.06–1.09 1.29 0.84–1.09 1.54–1.69 1.38–1.60 1.52–1.55 1.20–1.35 0.95–0.99 1.17–1.27U/LAS 1.47 0.78–0.79 1.25 0.87–1.09 2.33–2.39 1.51–1.82 2.25–2.35 1.24–1.37 1.15–1.20 1.16–1.25



TABLE 11. Measurements and ratios for the instar III larvae of selected species of Rhantus (acronyms as in Table 1); l,length; w, width.



continued next page

MeasureANI(n = 3)

ANT(n = 6)

BIN(n = 3)

CAG(n = 3)

CAL(n = 3)

CAP(n = 1)

CON(n = 1)

EXS(n = 2)

FEN(n = 2)

HL (mm) 2.63–2.66 3.19–3.36 2.19–2.25 2.50–2.53 2.30–2.43 2.54 2.88 2.53–2.63 2.49–2.50HW (mm) 2.35–2.58 3.06–3.16 2.08–2.20 2.38–2.46 2.35–2.53 2.48 2.63 2.23–2.30 2.33–2.40FRL (mm) 1.00–1.05 1.27–1.38 0.89–1.00 1.02–1.05 0.98–1.08 0.94 1.10 0.95–1.00 1.03–1.04OCW (mm) 1.38–1.50 1.98–2.00 1.35–1.43 1.41–1.49 1.35–1.45 1.48 1.48 1.58–1.63 1.30HL/HW 1.02–1.12 1.04–1.06 1.01–1.06 1.03–1.05 0.96–0.98 1.03 1.10 1.13–1.14 1.04–1.08HW/OCW 1.71–1.90 1.53–1.60 1.52–1.57 1.60–1.72 1.74–1.78 1.68 1.78 1.82–1.88 1.79–1.85A/HW 0.64–0.66 0.50–0.51 0.67–0.72 0.62–0.64 0.71–0.85 0.68 0.78 0.87–0.93 0.67–0.69A4/A1 0.82–0.86 0.81–0.85 0.74–0.89 0.73–0.83 0.53–0.59 0.88 0.83 0.97–0.98 1.07A4/A3 0.82–0.84 1.04–1.07 0.85–0.89 0.73–0.80 0.63–0.67 0.86 0.79 0.89–0.92 0.90–0.91MN(l/w) 2.92–3.11 2.86–2.93 2.85–3.01 2.97–3.22 3.02–3.04 2.94 2.99 2.89–3.01 3.16–3.35A/MP 1.38–1.43 1.37–1.39 1.42–1.45 1.38–1.47 1.46–1.48 1.46 1.62 1.63–1.69 1.24–1.25MP3/MP2 0.79–0.85 0.98–1.02 0.78–0.85 0.74–0.86 0.69–0.73 0.80 0.78 0.86–0.88 0.77–0.83GA/MP1 0.37–0.38 0.52–0.54 0.37–0.41 0.35–0.41 0.37–0.40 0.38 0.45 0.50 0.33–0.40MP/LP 1.26–1.28 0.99–1.06 1.16–1.20 1.13–1.19 1.12–1.17 1.19 1.14 1.05–1.06 1.18–1.23LP2/LP1 0.69–0.76 0.84–0.87 0.70–0.76 0.70–0.75 0.72–0.81 0.66 0.68 0.70–0.74 0.79–0.85L3 (mm) 6.66–7.28 8.71–8.82 6.09–6.37 6.77–6.90 6.54–7.10 6.86 7.32 6.45–6.50 6.69–6.71L3/HW 2.69–2.87 2.79–2.87 2.90–2.94 2.79–2.86 2.73–2.81 2.77 2.79 2.83–2.85 2.79–2.88LAS (mm) 2.18–2.35 3.04–3.12 1.80–2.00 1.98–2.08 3.55–3.68 2.18 3.00 2.78–2.80 2.58–2.65LAS/HW 0.85–0.93 0.96–1.02 0.82–0.92 0.83–0.86 1.46–1.51 0.88 1.14 1.22–1.25 1.07–1.14U (mm) 2.58–3.10 2.50–2.72 2.80–3.05 3.29–3.70 0.85–1.15 3.05 2.98 3.03–3.13 2.25–2.33U/HW 1.10–1.22 0.84–0.86 1.35–1.40 1.38–1.51 0.35–0.46 1.23 1.13 1.32–1.41 0.97–0.98U/LAS 1.18–1.31 0.83–0.89 1.49–1.65 1.61–1.82 0.24–0.31 1.40 0.99 1.08–1.13 0.85–0.90

MeasureFOR1

(n = 3)FRO(n = 1)

GRA(n = 2)

LAT(n = 1)

MON2

(n = 1)NOT(n = 2)

ORB(n = 1)

PHO(n = 2)

POE1

(n = 2)HL (mm) 2.85–2.88 2.55 2.40–2.45 2.68 3.75 2.65–2.73 2.90 2.40–2.58 3.10–3.35HW (mm) 2.80–3.03 2.43 1.85–1.95 2.35 4.28 2.48–2.50 2.77 2.25–2.50 3.48–3.55FRL (mm) 1.13–1.20 1.05 1.03–1.10 0.95 1.38 1.03–1.05 1.22 0.98–1.03 1.10–1.15OCW (mm) 1.56–1.70 1.50 1.28–1.35 1.33 2.03 1.63–1.68 1.97 1.23–1.35 1.58–1.60HL/HW 0.94–1.03 1.05 1.26–1.30 1.14 0.88 1.07–1.09 1.05 1.03–1.07 0.89–0.94HW/OCW 1.74–1.92 1.62 1.44–1.45 1.77 2.11 1.62–1.70 1.41 1.61–1.84 2.17–2.25A/HW 0.53–0.56 0.72 0.77–0.82 0.81 0.57 0.72–0.73 0.56 0.63–0.71 0.56A4/A1 0.65–0.71 0.98 0.95–1.08 0.87 0.57 0.91–0.98 0.90 0.72–0.77 0.49–0.52A4/A3 0.79–0.84 0.93 1.08–1.20 0.86 0.65 0.87–0.88 1.00 0.74–0.77 0.68–0.73MN(l/w) 2.73–2.98 2.92 3.14–3.23 2.95 3.10 2.80–2.86 2.70–2.73 2.89 3.41–3.43A/MP 1.27–1.32 1.52 1.65–1.74 1.59 1.24 1.58–1.61 1.60 1.41–1.53 1.30–1.35MP3/MP2 0.79–0.83 0.92 1.08–1.21 0.90 0.77 0.87 0.98 0.83–0.87 0.83–0.84GA/MP1 0.39–0.41 0.39 0.78–0.81 0.42 0.36 0.39–0.44 0.43 0.39 0.40–0.43MP/LP 1.39–1.43 ––– 1.03–1.06 1.09 1.39 1.00–1.02 1.09 1.14–1.20 1.26–1.30LP2/LP1 0.71–0.76 ––– 0.74–0.77 0.77 0.67 0.70–0.76 0.82–0.84 0.79 0.62–0.63L3 (mm) 7.11–7.33 7.21 6.21–6.47 6.74 10.01 6.94–6.96 7.61 6.26–6.78 7.96–8.05L3/HW 2.36–2.53 2.97 3.32–3.36 2.87 2.34 2.77–2.81 2.75 2.71–2.78 2.24–2.32LAS (mm) 1.98–2.20 2.80 2.83–2.88 3.15 2.65 2.85–2.93 3.20 1.48–1.55 2.28–2.30LAS/HW 0.67–0.75 1.16 1.47–1.53 1.34 0.62 1.15–1.17 1.16 0.62–0.66 0.64–0.66U (mm) 2.75–3.00 3.60 1.85–1.98 2.50 2.825 2.73–3.03 2.13–2.17 3.00–3.45 2.35–2.40U/HW 0.91–1.06 1.49 0.95–1.07 1.06 0.66 1.10–1.21 0.77–0.78 1.33–1.38 0.66–0.69U/LAS 1.25–1.52 1.29 0.64–0.70 0.79 1.07 0.96–1.03 0.67–0.68 2.03–2.23 1.03–1.04

MeasureSIG(n = 3)

SIM(n = 2)

SOC(n = 3)

SUT(n = 3)

VAL(n = 1)

WAL(n = 3)

HL (mm) 2.14–2.21 2.40–2.63 2.10–2.25 2.43–2.65 3.54 2.56–2.65HW (mm) 2.04–2.30 2.33–2.55 2.03–2.08 2.35–2.50 3.40 2.38–2.45FRL (mm) 0.85–0.94 0.95–1.13 0.88–0.93 0.95–1.05 1.44 0.99–1.05OCW (mm) 1.22–1.29 1.43 1.10–1.15 1.20–1.35 1.90 1.25–1.30HL/HW 0.96–1.05 1.03 1.04–1.11 1.08–1.11 1.04 1.08HW/OCW 1.58–1.67 1.63 1.80–1.84 1.84–2.01 1.79 1.89–1.90A/HW 0.62–0.74 0.66–0.70 0.64–0.66 0.73–0.83 0.52 0.82–0.87A4/A1 0.87–1.00 0.76–0.77 0.74–0.78 1.03–1.05 0.73–0.87 0.88–0.98A4/A3 0.81–0.92 0.79–0.88 0.77–0.78 0.89–0.98 0.76 0.88–0.94MN(l/w) 2.42–2.86 2.86–3.01 2.87–2.97 2.86–3.00 2.77–2.84 2.69–2.86A/MP 1.43–1.53 1.60–1.64 1.43–1.48 1.44–1.53 1.24–1.25 1.57–1.62



TABLE 11. Continue.

1 from Alarie & Wang (2004); 2 Balke et al. (2007)

Description of larvae of Rhantus signatus (Fabricius, 1775)

Source of material. The larvae studied were reared ex ovo in the laboratory from adults collected by M.Archangelsky and M.C. Michat at the following locality: Argentina, Buenos Aires City, IX.2000.

First-instar larva (n = 5) (Figs 147–151)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Dorsal surface of head light brown except for anterolateral margins of frontoclypeus and several

maculae on central portion of frontoclypeus yellowish; head appendages yellowish to light brown, apex of A3light brown; thoracic and abdominal sclerites light brown; legs and urogomphus yellowish to light brown.

Head. Head capsule (Fig. 147). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulaeover dorsal surface; adnasaliae converging inward; occipital carina well defined; parietale distinctlyconstricted at level of occipital region, with microspinulae over posterior 1/2 of dorsal surface. Antenna.Microspinulae lacking, antennomere III with a ventroapical spinula. Maxilla. Palpus lacking microspinulae.Labium. Palpus lacking microspinulae.

Thorax. Legs (Figs 148–149). Microspinulae present on dorsal margin of coxae and ventral margin offemora, tibiae and tarsi; tarsal claws with microspinulae covering basal 1/2 of ventral margin.

Abdomen. Urogomphus (Fig. 151). Microspinulae present over basal 1/2.Chaetotaxy. Position and number of additional setae on legs are shown in Table 4; primary pore FRe

present (Fig. 147); anterior margin of frontoclypeus with 16–23 digitiform to spiniform lamellae clypeales;A3 with two additional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorterthan palpifer and galea; stipes lacking additional setae along inner margin; anterodorsal primary setae ofprementum minute; procoxal seta CO7 articulated distally, at about level of articulation of seta CO6; meso-and metafemoral seta FE5 elongate and hair-like (Fig. 149); seta TI7 elongate and hair-like (Fig. 149);urogomphus (Fig. 151) with one additional seta; primary seta UR2 about as long as seta UR3; primary setaUR4 shorter than any of setae UR5, UR6 or UR8; seta UR5 articulated posterior to articulation of seta UR7;seta UR7 shorter than any of setae UR5, UR6 or UR8.

Second-instar larva (n = 4)As first-instar larva except as follows:Colour. Dorsal surface of head yellowish to light brown except for several yellowish maculae on central

portion of frontoclypeus, anterior to occipital suture and medial to each ocular area; ventral surface yellowishto light brown; head appendages yellowish, distal 1/2 of mandibles light brown; thoracic and, to a lesserextent abdominal sclerites with a pattern of white maculae on a yellowish to light brown background,membranous parts yellowish; legs and urogomphus yellowish to light brown.

Head. Maxilla. Microspinulae lacking along inner margin of stipes.

MeasureSIG(n = 3)

SIM(n = 2)

SOC(n = 3)

SUT(n = 3)

VAL(n = 1)

WAL(n = 3)

MP3/MP2 0.90–0.94 0.77–0.79 0.79–0.88 0.83–0.94 0.91–0.95 0.77–0.79GA/MP1 0.41–0.43 0.41–0.45 0.32–0.44 0.33–0.44 0.35–0.36 0.35–0.39MP/LP 1.11–1.18 1.05–1.15 1.20–1.25 1.06–1.15 1.17–1.20 1.05–1.15LP2/LP1 0.75–0.77 0.71–0.73 0.69–0.75 0.69–0.76 0.79 0.60–0.66L3 (mm) 5.42–5.97 6.05–6.42 5.29–5.44 6.38–6.71 8.84–8.88 6.61–6.70L3/HW 2.58–2.89 2.52–2.60 2.61–2.65 2.68–2.75 2.60–2.61 2.70–2.79LAS (mm) 1.86–1.94 2.15–2.33 1.33–1.43 2.33–2.90 2.80 2.58–2.70LAS/HW 0.84–0.95 0.91–0.93 0.65–0.70 0.99–1.20 0.82 1.05–1.11U (mm) 2.52–2.94 2.28 2.65–2.70 2.25–3.03 2.36–2.54 2.35–2.58U/HW 1.23–1.44 0.89–0.98 1.30–1.32 0.96–1.25 0.69–0.75 0.99–1.05U/LAS 1.30–1.58 0.98–1.06 1.88–2.02 0.90–1.04 0.84–0.91 0.89–1.00



Thorax. Legs. Anteroventral spinulae strongly developed on profemur, tibiae and tarsi; metacoxa withpredominantly short hair-like secondary setae along dorsal margin; metafemoral natatory setae present alongdistal 1/2 of dorsal margin.




Third-instar larva (n = 3) (Figs 152–156)As second-instar larva except as follows:Colour. Dorsal surface of head greyish to light brown except for several maculae on central portion of

frontoclypeus, posterior to stemmata, anterior to occipital suture and medial to each ocular area yellowish(Fig. 152); ventral surface yellow except for posterolateral areas light brown bearing several small yellowishmaculae; head appendages yellowish except for apices of A3, A4, MP3 and LP2 light brown and distal 1/2 ofmandible brown; thoracic and abdominal sclerites greyish to light brown, with pattern of yellowish maculae;sclerites VII and VIII without this pattern; legs yellowish; U yellowish, distal portion light brown.



Remarks. As stated above (see under R. calileguai), larvae of the Neotropical species R. signatus, R.anisonychus and R. calileguai all share the presence of a variable number of both elongate hair-like and shortspine-like secondary setae along the inner margin of urogomphus. Larvae of R. signatus can readily bedistinguished from those of R. anisonychus and R. calileguai by the following combination of characters: size,lack of microspinulae along inner margin of stipes (second and third instar), weakly developed anteroventralspinulae on profemur (second and third instar) (Fig. 153), shorter dorsal secondary setae on metacoxa (bestseen in third instar), number of natatory setae on mesofemur and metatibia (Tables 6, 8), relative elongation ofLAS and urogomphus compared to HW (Tables 9–11), presence of microspinulae over posterior 1/2 ofparietale basal 1/2 of urogomphus and most of anterior surface of legs, and absence on head appendages (firstinstar).

The third-instar larva of R. signatus was previously described by Crespo (1987)

Description of larvae of Rhantus simulans Régimbart, 1908

Source of material. The larvae studied were collected in association with adults by L. Hendrich at thefollowing locality: Western Australia. D’Entrecasteaux NP, 5 km south Northcliffe, 12 masl, 5.I.2007.Exposed, shallow pool without any vegetation but rich in rotten leaves and twigs. Larvae were sitting amongthe leaves right at the edge of the pool. Two species of Rhantus are present in SW Australia. The association issafe as R. simulans was the only species of Rhantus found in that pool.

First- and second-instar larvaeNo specimens available for study.

Third-instar larva (n = 2) (Figs 157–161)



Measurements and ratios aimed to characterize body shape shown in Table 11.Colour. Body predominantly piceous black; head capsule black with a reticulate yellow colour pattern

mesally over frontoclypeus and parietale (Fig. 157); head appendages yellow to piceous, A1, A2, A3, A4,MP1, MP2, MP3 and LP2 infuscate apically; body terga predominantly piceous black; protergum with anirrorate yellowish colour pattern, yellowish maculae reduced on both meso- and metatergum; abdominal tergaeach with a small yellowish macula mesally; abdominal segments VII and VIII paler than rest of body; legsand urogomphus yellow.

Head. Maxilla. Microspinulae present along inner margin of stipes.Thorax. Legs (Figs 158–159). Anteroventral spinulae strongly developed on profemur, tibiae and tarsi;

metacoxa with dorsal secondary setae predominantly elongate; metafemoral natatory setae present alongdistal 1/2 of dorsal margin.


parietale with 9–10 temporal spine-like setae, most anterior ones articulated at about level of posterior marginof ocularium; stipes with minute secondary setae along inner margin; dorsal surface of last abdominalsegment covered with both spine-like and hair-like secondary setae (Fig. 160); urogomphus with secondarysetae along both inner and outer margins, outer margin with elongate and hair-like setae only, except for oneshort spine-like seta proximally (Fig. 161).

Remarks. The Australian species Rhantus simulans belongs to the group of species characterized by thepresence of elongate and hair-like natatory setae and one short spine-like seta along outer margin ofurogomphus (R. consputus, R. validus, R. notaticollis, R. wallisi, R. suturellus, R. suturalis, R. fennicus, R.latitans, R.exsoletus). Compared to these species, larvae of R. simulans can readily be distinguished bydistribution.

Description of larvae of Rhantus socialis (C. O. Waterhouse, 1876)

Source of material. The larvae studied were collected in association with adults by A. Martens at thefollowing locality: Mascarene Islands, Rodriguez. Baleine river, near St. Gabriel, 11.VIII.2005; smallstream west of Cotton Bay, 7.VIII.2005. The association is safe as R. socialis is the only species of Rhantusfound in Rodriguez.

First-instar larva (n = 3) (Figs 162–166)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Body predominantly pale brown; head capsule brown, paler around ocularia; head appendages

yellow, A3, MP3 and LP2 infuscate apically; thoracic and abdominal terga dark yellow to pale brown; legscreamy white to pale brown; urogomphus dark yellow, dark brown proximally over a short distance.

Head. Head capsule (Fig. 162). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulaeover dorsal surface; adnasaliae converging inward; occipital carina well defined; parietale distinctlyconstricted at level of occipital region, with microspinulae over most of dorsal surface. Antenna.Microspinulae lacking, antennomere III with a ventroapical spinula. Maxilla. Palpus lacking microspinulae.Labium. Palpus lacking microspinulae.

Thorax. Legs (Figs 163–164). Microspinulae present over most of anterior surface; tarsal claws withmicrospinulae covering basal 1/3 of ventral margin.

Abdomen. Urogomphus (Fig. 166). Microspinulae present over most of its surface.Chaetotaxy. Position and number of additional setae on legs are shown in Table 4; primary pore FRe

present (Fig. 162); anterior margin of frontoclypeus with 21–22 digitiform lamellae clypeales; A3 with twoadditional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorter than palpifer



and galea; stipes lacking additional setae along inner margin; anterodorsal primary setae of prementumminute; procoxal seta CO7 articulated proximally to articulation of seta CO6; meso- and metafemoral setaFE5 elongate and hair-like (Fig. 164); seta TI7 elongate and hair-like (Fig. 164); urogomphus (Fig. 166) withone additional seta; primary seta UR2 about as long as seta UR3; primary seta UR4 shorter than any of setaeUR5, UR6 or UR8; seta UR5 articulated posterior to articulation of seta UR7; seta UR7 shorter than any ofsetae UR5, UR6 or UR8.

Second-instar larva (n = 2)As first-instar larva except as follows:Colour. Dorsal surface of head yellowish with a brown mottled pattern on frontoclypeus and parietale;

thoracic terga yellow with an irrorate maculation pattern mesally.Head. Maxilla. Microspinulae present along inner margin of stipes.Thorax. Legs. Anteroventral spinulae weakly developed on profemur and meso- and metatibia, well

developed on protibia and tarsi; metacoxa with predominantly short hair-like secondary setae along dorsalmargin; metafemoral natatory setae present along distal 1/2 of dorsal margin.




Third-instar larva (n = 3) (Figs 167–171)As second-instar larva except as follows:Colour. Darker; abdominal segments I–VI paler mesally; abdominal segment VII dark yellow.Thorax. Legs (Figs 168–169). Metafemoral natatory setae present along distal 1/2 of dorsal margin.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 8 and Figs 168–169;


Remarks. As mentioned above, the three African species R. socialis, R. capensis and R. phocaenarumbelong to a group of species characterized by the presence of a variable number of elongate hair-like and shortspine-like secondary setae along the outer margin of urogomphus (Fig. 171) (along with R. signatus, R.frontalis, R. binotatus, R. calileguai, R. anisonychus). Larvae of R. socialis can be distinguished from theother two African species by the following combination of characters: smaller size, absence of microspinulaealong the inner margin of stipes (second and third instar), reduced spinulae along the anteroventral margin ofmeso- and metatibia (second and third instar), number of natatory setae on metatibia (Tables 6, 8), relativeelongation of LAS and urogomphus compared to HW (Tables 9–11) and proximal articulation of procoxalseta CO7 (first instar).

Description of larvae of Rhantus suturalis (Macleay, W.S., 1825)

Source of material. The larvae studied were collected in association with adults by L. Hendrich at thefollowing locality: Uzbekistan, Tashkent, Bektemir, 450 m, Chirchiq, floodplains, 19–21.IV.2009. Theidentification is safe as R. suturalis is the only Rhantus species found in Uzbekistan.

First- and second-instar larvae



No specimens available for study.

Third-instar larva (n = 3) (Figs 172–176)Measurements and ratios aimed to characterize body shape shown in Table 11.Colour. Body predominantly piceous grey; head capsule piceous, with a yellow reticulate pattern mesally

over frontoclypeus and parietale; occiput broadly yellow with piceous maculae mesally (Fig. 172); headappendages yellow, apices of A3, A4, MP2, MP3, and LP2 infuscate; body terga predominantly piceous topale grey; protergum with irrorate yellow maculae mesally, broadly yellow along lateral margins; meso- andmetaterga with few yellowish maculae; abdominal tergum VIII pale grey to dark yellow; legs andurogomphus yellowish.


metacoxa with dorsal secondary setae predominantly short; metafemoral natatory setae present along distal 2/3 of dorsal margin.


parietale with 7–10 temporal spine-like setae, most anterior ones articulated at about level of posterior marginof ocularium; stipes lacking minute secondary setae along inner margin; dorsal surface of last abdominalsegment covered with both spine-like and hair-like secondary setae (Fig. 175); urogomphus with secondarysetae along both inner and outer margins, outer margin with elongate and hair-like setae only, except for oneshort and spine-like seta proximally (cf. Fig. 176).

Remarks. Rhantus suturalis belongs to the group of species characterized by the presence of elongatehair-like natatory setae and one short spine-like seta along outer margin of urogomphus (R. consputus, R.validus, R. notaticollis, R. wallisi, R. simulans, R. fennicus, R. latitans, R. exsoletus, R. suturellus). Comparedto these species, larvae of R. suturalis can readily be distinguished by the following combination ofcharacters: absence of microspinulae along inner margin of stipes, presence of short hair-like setae alongdorsal margin of metacoxa, number of natatory setae on metatibia (second and third instar) (Table 6, 8),presence of one secondary seta on protrochanter, absence of PV secondary setae on tarsi (Tables 7, 8) andrelative elongation of LAS and urogomphus compared to HW (Tables 9–11).

The larva of this species was previously described by Galewski (1963).

Description of larvae of Rhantus suturellus (Harris, 1828)

Source of material. The larvae studied were reared ex ovo by Y. Alarie from adults collected at the followinglocality: Canada, Québec, Lac à la Tortue, sphagnum bog, 20.IV.1988. Additional specimens were collectedin association with adults by A.N. Nilsson at the following locality: Sweden, Västerbotten province, Byske,Romelsön island, bog pool, 22.VI.2003.

First-instar larva (n = 2) (Figs 177–181)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Body predominantly piceous black; head capsule, head appendages and legs dark brown.Head. Head capsule (Fig. 177). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulae

over dorsal surface; adnasaliae converging inward; occipital carina well defined; parietale slightly constrictedat level of occipital region, with microspinulae over posterior 1/2 of dorsal surface. Antenna. Microspinulaelacking, antennomere III with a ventroapical spinula. Maxilla. Palpus lacking microspinulae. Labium. Palpuslacking microspinulae.

Thorax. Legs (Figs 178–179). Microspinulae reduced to dorsal margin of coxae and ventral margin of



femora, tibiae and tarsi; tarsal claws with microspinulae covering basal 3/4 of ventral margin.Abdomen. Urogomphus (Fig. 181). Microspinulae present over most of its surface.Chaetotaxy. Position and number of additional setae on legs are shown in Table 4; primary pore FRe

present (Fig. 177); anterior margin of frontoclypeus with 24–26 spatulate lamellae clypeales; A3 with twoadditional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorter than palpiferand galea; stipes lacking additional setae along inner margin; anterodorsal primary setae of prementumminute; procoxal seta CO7 articulated distally, at about level of articulation of seta CO6; meso- andmetafemoral seta FE5 elongate and hair-like (Fig. 179); seta TI7 elongate and hair-like (Fig. 179);urogomphus (Fig. 181) with one additional seta; primary seta UR2 about as long as seta UR3; primary setaUR4 as long as any of setae UR5, UR6 or UR8; seta UR5 articulated posterior to articulation of seta UR7; setaUR7 shorter than any of setae UR5, UR6 or UR8.

Second-instar larva (n = 3)As first-instar larva except as follows:Colour. A1, A2, A3, A4, LP1 and LP2 yellowish proximally.Head. Maxilla. Microspinulae lacking along inner margin of stipes.Thorax. Legs. Anteroventral spinulae strongly developed on profemur, tibiae and tarsi; metacoxa with

predominantly elongate hair-like secondary setae along dorsal margin; metafemoral natatory setae presentalong distal 1/2 of dorsal margin.


temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith minute secondary setae along inner margin; dorsal surface of last abdominal segment covered with bothspine-like and hair-like secondary setae (cf. Fig. 185); urogomphus with secondary setae along both inner andouter margins, outer margin with elongate and hair-like setae only, except for one short and spine-like setaproximally (cf. Fig. 186).


Third-instar larva (n = 7) (Figs 182–186)As second-instar larva except as follows:Colour. Body slightly paler; head capsule dark grey with an irrorate yellowish colour pattern, occiput

yellowish laterally (Fig. 182); protergum dark yellow along lateral margins, with a few yellowish maculaemesally.



Remarks. The Holarctic Rhantus suturellus belongs to the group of species characterized by the presenceof elongate hair-like natatory setae and one short spine-like seta along outer margin of urogomphus (R.consputus, R. validus, R. notaticollis, R. wallisi, R. simulans, R. fennicus, R. latitans, R. exsoletus, R.suturalis). Compared to these species, larvae of R. suturellus can readily be distinguished by the followingcombination of characters: absence of microspinulae along inner margin of stipes (second and third instar),presence of elongate hair-like setae along the dorsal margin of metacoxa (best seen in third instar), number ofnatatory setae on metatibia (second and third instar) (Table 6, 8), relative elongation of LAS and urogomphuscompared to HW (Tables 9–11), lamellae clypeales spatulate (first instar) (Fig. 177), absence of additionalsetae along the inner margin of stipes (first instar), distal articulation of procoxal seta CO7 (first instar),presence of additional setae along dorsal margin of pro- and mesotibia, and of at least two ventral additionalsetae on tarsi (first instar) (Figs 178–179, Table 4), microspinulae reduced on coxae and femora, well-



developed on urogomphus (first instar).All instars of this species were described previously by Galewski (1963). The third-instar larva was

possibly first described by Bertrand (1928) under the name R. bistriatus (Bergsträsser) (Galewski 1963).

Description of larvae of Rhantus validus Sharp, 1882

Source of material. Larvae were collected in association with adults by M. Archangelsky and M.C. Michat atthe following locality: Argentina, Chubut province, stream arising from Laguna La Z, surroundings ofEsquel City, 2003.

First-instar larva (n = 1) (Figs 187–195)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour. Dorsal surface of cephalic capsule brown except for one light brown macula enclosing each egg

burster; head appendages testaceous to light brown; thoracic and abdominal tergites testaceous to light brown;legs testaceous to light brown except for coxae somewhat paler and medial portion of trochanter testaceous;urogomphus testaceous to light brown.

Head. Head capsule (Fig. 187). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulaeover dorsal surface; adnasaliae converging inward; occipital carina well defined; parietale distinctlyconstricted at level of occipital region, with microspinulae over most of dorsal surface. Antenna.Microspinulae lacking, antennomere III with a ventroapical spinula. Maxilla (Figs 192–193). Palpus lackingmicrospinulae. Labium (Figs 194–195). Palpus lacking microspinulae.

Thorax. Legs (Figs 188–189). Microspinulae present all over surface; tarsal claws with microspinulaecovering basal 3/4 of ventral margin.


absent (Fig. 187); anterior margin of frontoclypeus with 34–35 spatulate lamellae clypeales; A3 with twoadditional ventroapical pores; primary seta MX7 elongate, subequal in length to galea (Fig. 193); primary setaMX5 shorter than galea, longer than palpifer (Fig. 192); stipes with one additional seta along inner margin(Fig. 192); anterodorsal primary setae of prementum elongate (Fig. 194); procoxal seta CO7 articulateddistally, at about level of articulation of seta CO6; meso- and metafemoral seta FE5 short and spine-like (Fig.189); seta TI7 elongate and hair-like (Fig. 189); urogomphus (Fig. 191) with several additional seta; relativelength of setae UR2–UR8 not defined owing to presence of several additional setae similar in size.

Second-instar larva (n = 1)As first-instar larva except as follows:Colour. Darker; head capsule with an irrorate yellowish colour pattern dorsally; occiput with one mesal

and two lateral yellow maculae.Head. Maxilla. Microspinulae present along inner margin of stipes.Thorax. Legs. Anteroventral spinulae strongly reduced on profemur, well-developed on tibiae and tarsi;

metacoxae with predominantly elongate hair-like secondary setae along dorsal margin; metafemoral natatorysetae present along distal 1/2 of dorsal margin.


temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith elongate spine-like secondary setae along inner margin; dorsal surface of last abdominal segmentcovered with both spine-like and hair-like secondary setae (cf. Fig. 199); urogomphus with secondary setaealong both inner and outer margins, outer margin with elongate and hair-like setae only, except for one shortand spine-like seta proximally (cf. Fig. 200).




Third-instar larva (n = 1) (Figs 196–200)As second-instar larva except as follows:Colour. Dark brown; A1, A2, A3, A4, MP2, MP3 and LP2 paler proximally.Thorax. Legs (Figs 197–198). Metafemoral natatory setae present along distal 1/2 of dorsal margin.Chaetotaxy. Number and position of secondary setae on legs are shown in Table 8 and Figs 197–198;

parietale with 13 temporal spine-like setae.Measurements and ratios aimed to characterize body shape shown in Table 11.

Remarks. Larvae of the Neotropical R. validus are characterized by several unique features withinRhantus. In addition to their large size, larvae are characterized by the presence of elongate and spine-likesetae along inner margin of stipes (Fig. 192) (shared with R. calidus), elongate setae along anterodorsalmargin of prementum (Fig. 194) (shared with R. grapii), larger number of lamellae clypeales (first instar),longer primary setae MX5 and MX7 (Figs 192–193), and presence of several additional setae on urogomphus(first instar) (Fig. 191).

Description of larvae of Rhantus wallisi Hatch, 1953

Source of material. The larvae studied were reared ex ovo by Y. Alarie from adults collected at the followinglocality: Canada, Ontario, Sudbury, Lake Laurentian Conservation Area, pond, 20.V.1998; ManitoulinIsland, roadside ditch at Hwy 540, 9 km east of Mildrum Bay, 17.V.2001.

First-instar larva (n = 5) (Figs 201–205)Measurements and ratios aimed to characterize body shape shown in Table 9.Colour (freshly killed specimens). Body yellow to piceous; head capsule testaceous, with a cloudy light

grey pattern over frontoclypeus and parietale; head appendages greyish black except MP1 and LP1 yellow;thoracic terga grey, faintly yellow; abdominal terga grey; legs yellowish grey; urogomphus dark grey.

Head. Head capsule (Fig. 201). Frontoclypeus extending beyond tips of adnasaliae, lacking microspinulaeover dorsal surface; adnasaliae converging inward; occipital carina well defined; parietale slightly constrictedat level of occipital region, with microspinulae over posterior 1/2 of dorsal surface. Antenna. Microspinulaelacking; antennomere III with a ventroapical spinula. Maxilla. Palpus lacking microspinulae. Labium. Palpuslacking microspinulae.

Thorax. Legs (Figs 202–203). Microspinulae reduced to dorsal margin of coxae and ventral margin offemora, tibiae and tarsi; tarsal claws with microspinulae covering basal 2/3 of ventral margin.


present (Fig. 201); anterior margin of frontoclypeus with 24–25 spatulate lamellae clypeales; A3 with twoadditional ventroapical pores; primary seta MX7 shorter than galea; primary seta MX5 shorter than palpiferand galea; stipes lacking additional setae along inner margin; anterodorsal primary setae of prementumminute; procoxal seta CO7 articulated distally, at about level of articulation of seta CO6; meso- andmetafemoral seta FE5 elongate and hair-like (Fig. 203); seta TI7 elongate and hair-like (Fig. 203);urogomphus (Fig. 205) with one additional seta; primary seta UR2 about as long as seta UR3; primary setaUR4 as long as any of setae UR5, UR6 or UR8; seta UR5 articulated posterior to articulation of seta UR7; setaUR7 shorter than any of setae UR5, UR6 or UR8.

Second-instar larva (n = 5)As first-instar larva except as follows:Colour. Predominantly testaceous; head capsule with a narrow blackish stripe along coronal suture and



lateral margins of parietale; head appendages piceous black, most articles darker apically; thoracic andabdominal terga I-VII yellowish, with a faint greyish pattern mesally, black along sutural line and post-scutellum; last abdominal segment piceous over siphon; legs predominantly yellowish; urogomphus piceousblack, yellowish proximally.

Head. Maxilla. Microspinulae lacking along inner margin of stipes.Thorax. Legs. Anteroventral spinulae strongly developed on profemur, tibiae and tarsi; metacoxa with

predominantly elongate hair-like secondary setae along dorsal margin; metafemoral natatory setae presentalong distal 1/2 of dorsal margin.


temporal spine-like setae, most anterior ones articulated at about level of posterior margin of ocularium; stipeswith minute secondary setae along inner margin; dorsal surface of last abdominal segment covered with bothspine-like and hair-like secondary setae (cf. Fig. 209); urogomphus with secondary setae along both inner andouter margins, outer margin with elongate and hair-like setae only, except for one short and spine-like setaproximally (Fig. 210).


Third-instar larva (n = 7) (Figs 206–210)As second-instar larva except as follows:Colour. Body yellow; most body terga with an irrorate greyish pattern; head appendages predominantly

yellow, A1, A2, A3, MP2, MP3 and LP2 piceous apically, A4 all piceous; legs yellow; urogomphuspredominantly yellow, piceous apically.



Remarks. The Nearctic R. wallisi belongs to the group of species characterized by the presence ofelongate and hair-like natatory setae and one shorter spine-like seta along the outer margin of urogomphus(Fig. 210) (R. consputus, R. validus, R. notaticollis, R. suturellus, R. suturalis, R. simulans, R. fennicus, R.latitans, R. exsoletus). In the Nearctic region, larvae of this species can only be confused with those of R.suturellus, from which they can be distinguished by the characters mentioned in the key (see also under R.suturellus).

Character Analysis

The analysis of the data matrix using TNT resulted in 4800 most parsimonious trees of 111 steps. The strictconsensus was calculated (Fig. 211). The second analysis using implied weighting produced 1400 trees, theconsensus of which showed a better resolution than the previous analysis (Fig. 212). In both analyses, thesupport obtained was high for the Colymbetini clade but low for the internal nodes.

Discussion

Based on this study, the monophyly of the Colymbetini is indicated by at least five synapomorphies (i.e.,found only in this group and unreversed) in regard of outgroups chosen. Larvae of Colymbetini have evolved(i) a relatively more distal articulation of the primary pore ANg on antennomere IV (character 07), (ii) a muchreduced sensorial appendage (A3’) (character 10), (iii) a relatively more proximal articulation of the primary



seta FE1 (character 32), (iv) the presence of tarsal claw basoventral spinulae in first instar (character 43)(whereas tarsal spinulae are sometimes reduced or lacking in instar III of some species, this study suggeststhat they always occur in the first instar), and (v) the presence of a one-segmented urogomphus (character 53).It is noteworthy that larvae of the Colymbetini are also characterized by (i) the presence of additionalventroapical pores on antennomere III (character 12), (ii) elongate and hair-like primary seta FE6 (character36) and (iii) the presence of secondary natatory setae on legs (character 46). These three character states areconsidered of a lesser evolutionary meaning knowing that they have evolved several times independentlywithin the Dytiscidae, namely in Lancetes Sharp (Alarie et al. 2002; Alarie & Hughes 2006).

The present paper represents the most comprehensive study of the larval morphology of world species ofRhantus ever published, which incorporates species from all major zoogeographic regions (Table 1).Interestingly, our phylogenetic analysis (Fig. 212) suggests that Rhantus is polyphyletic in agreement withrecent studies based on adult (Miller 2001), larval (Alarie & Hughes 2006; Michat 2005) and molecular(Ribera et al. 2008) data sets. Indeed, larvae of this genus reveal to be fairly diverse morphologically, whichresulted into closer relationships of Rhantus monteithi and R. grapii with some other genera of theColymbetini than other species of the genus (Figs 211–212). Larvae of R. grapii differ strongly from those ofany other Rhantus species studied by the following unique character states: (i) frontoclypeus extendingbeyond adnasaliae (character 05) (Fig. 101), (ii) adnasaliae diverging outward (character 06) (Fig. 101), (iii)antennomere 3 lacking a ventral spinula (character 11), (iv) primary seta MX5 longer than labial palpomere 1(character 18) (Fig. 102), (v) galea elongate (character 20) (Fig. 102), (vi) presence of additional setae alongdorsal margin of femur (character 33) (Fig. 103), and (vii) primary seta UR2 longer than seta UR3 (character55) (Fig. 106). Larval morphology clearly reinforces the hypothesis that R. grapii belongs to a distinct lineagewithin the Colymbetini as indicated in previous studies based on adult (Nilsson 2001) and molecular data sets(Ribera et al. 2008). In that regard a study of the larval morphology of R. sinuatus (LeConte), with R. grapiithe only other Rhantus species placed in the subgenus Nartus Zaitzev would be of the utmost interest. Whereas the tree topologies presented in this paper (Figs 211–212) are hampered by weak node supports,some hypotheses warrant to be discussed. First, we suggest that the Neotropical species R. orbignyi, R.antarcticus, R. calidus and R. validus may represent a distinct lineage within the Colymbetini. All thesespecies diverge at the basis of the trees prior to all other Colymbetini studied and are characterized by severalunique larval character states: (i) the absence of the primary pore FRe (character 02) (Figs 1, 40, 127, 187),the short and spine-like aspect of (ii) the meso- and (iii) metafemoral seta FE5 (characters 34 and 35) (Figs 11,42, 129, 189) and the absence of additional setae both on (iv) protibia (character 37) and (v) tarsus (character41) (Figs 10–11, 41–42, 128–129, 188–189). All these species but R. validus also are characterized by a shortand spine-like primary seta TI7 (character 40) (Figs 10–11, 41–42, 128–129) and by the absence of secondarysetae on urogomphi (character 51) (Figs 19, 50, 136), two unique features within the Colymbetini. Amongthese species, R. calidus stands as the most divergent species being characterized by the secondarysubdivision of (i) the antennomeres 2–4 (character 14) (Fig. 46), (ii) the maxillary palpomeres 2–3 (character17), and (iii) the labial palpomere 2 (character 26) and the articulation of the primary seta UR5 anterior to setaUR7 (character 57) (Fig. 44). Larvae of both R. calidus and R. validus share the presence of three elongatesetae along inner margin of stipes (character 21) (Figs 192–193) and the presence of several elongate setae onthe prementum (character 28) (Figs 194–195) (possibly homoplastic in R. grapii).

The Pacific species R. poellerbaurae and R. monteithi diverged at the basis of our trees, closer to otherColymbetini genera (namely Carabdytes upin Balke, Hendrich & Wewalka, 1992) in accordance with a recentstudy based on molecular data (Balke et al. 2009). In the absence of first instar for each of these species,however, such hypothesis is weakly supported since several of the characters used in this study are from first-instar larvae.

Our study also suggests that the bulk of the Rhantus species studied (18 of 24) may be closely relatedphylogenetically. With few exceptions (R. simulans, R. calileguai, R. phocaenarum, R. socialis), all thesespecies have a Nearctic and/or Palearctic distribution. Larvae of these species are characterized by (i) thepresence of an elongate and hair-like meso- and metafemoral seta FE5 (characters 34 and 35) (Figs 22, 32, 53,



68, 78, 88, 119, 149, 164, 179, 203), and the presence of additional setae on (ii) protibia (character 37), (iii)tarsus (character 41) (Figs 21–22, 31–32, 52–53, 67–68, 77–78, 87–88, 118–119, 148–149, 163–164, 178–179, 202–203) and (iv) metafemur (character 42) (Figs 22, 32, 53, 68, 78, 88, 119, 149, 164, 179, 203)(homoplastic in R. grapii and some Colymbetini genera). Among these, larvae of R. signatus, R.phocaenarum, R. frontalis, R. capensis, R. calileguai, R. binotatus, R. anisonychus, R. socialis, and R.formosanus all share the presence of a variable number of spiniform secondary setae along the outer margin ofurogomphus (character 50) (Figs 29, 39, 60, 65, 100, 146, 156, 171) and the presence of seta UR4 shorter thansetae UR5, UR6 and UR8 (character 56, only seen in first-instar larvae) (Figs 24, 34, 55, 141, 151, 166). Acloser phylogenetic relationship of Palearctic and Nearctic elements of Rhantus is in accordance with a recentstudy based on molecular data (Balke et al. 2009).

Acknowledgements

Financial support was provided by the Natural Sciences and Engineering Research Council of Canada in theform of an operating research grant to Y.A. Field and laboratory work by M.C.M. was supported in part bygrant PIB X846 from the Universidad de Buenos Aires and a postgraduate scholarship from CONICET. Fieldwork by M.A. was partially supported by the grant PICT 01–06156 from the ‘Agencia Nacional de

Promociones Cientificas Técnicas (Argentina); this is contribution No 29 from LIESA. Field work by L.H.was supported by Deutsche Forschungsgemeinschaft grant BA 2152/4-1 to Dr M. Balke (ZoologischeStaatssammlung, Munich, Germany).

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FIGURES 1–2. Rhantus antarcticus nahueli (first-instar larva), head capsule: (1) dorsal aspect (colour pattern notrepresented); (2) ventral aspect. EB, egg bursters: FR, frontoclypeus; PA, parietale; TP, tentorial pits. Numbers andlowercase letters refer to primary setae and pores, respectively. Scale bar = 0.20 mm.



FIGURES 3–9. Rhantus antarcticus nahueli (first-instar larva), head appendages: (3–4) antenna, (3) dorsal aspect; (4)ventral aspect; (5–6) maxilla, (5) dorsal aspect; (6) ventral aspect; (7–8) labium; (7) dorsal aspect; (8) ventral aspect; (9)mandible, dorsal aspect. AN, antenna; LA, labium; MN, mandible; MX, maxilla. Numbers and lowercase letters refer toprimary setae and pores, respectively; filled squares and triangles refer to additional setae and pores, respectively. Scalebars = 0.10 mm.



FIGURES 10–14. Rhantus antarcticus nahueli (first-instar larva): (10–11) metathoracic leg; (10) anterior aspect; (11)posterior aspect; (12–13) abdominal segment eight; (12) dorsal aspect; (13) ventral aspect; (14) urogomphus, dorsalaspect; AB, abdominal segment eight; CO, coxa; FE, femur; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter; UR,urogomphus. Numbers and lowercase letters refer to primary setae and pores, respectively; filled squares refer toadditional setae. Scale bars = 0.20 mm.



FIGURES 15–19. Rhantus antarcticus nahueli (third-instar larva): (15) head capsule, dorsal aspect (not all secondarysetae represented); (16–17) prothoracic leg; (16) anterior aspect; (17) posterior aspect; (18) abdominal segment eight,dorsal aspect; (19) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 20–24. Rhantus anisonychus (first-instar larva): (20) head capsule, dorsal aspect (colour pattern notrepresented); (21–22) metathoracic leg; (21) anterior aspect; (22) posterior aspect; (23) abdominal segment eight, dorsalaspect; (24) urogomphus, dorsal aspect. AB, abdominal segment eight; CO. coxa; EB, egg bursters; FE, femur; FR,frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter, UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.20mm.



FIGURES 25–29. Rhantus anisonychus (third-instar larva): (25) head capsule, dorsal aspect (not all secondary setaerepresented); (26–27) prothoracic leg; (26) anterior aspect; (27) posterior aspect; (28) abdominal segment eight, dorsalaspect; (29) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 30–34. Rhantus binotatus (first-instar larva): (30) head capsule, dorsal aspect (colour pattern notrepresented); (31–32) metathoracic leg; (31) anterior aspect; (32) posterior aspect; (33) abdominal segment eight, dorsalaspect; (34) urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur; FR,frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter; UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.20mm.



FIGURES 35–39. Rhantus binotatus (third-instar larva): (35) head capsule, dorsal aspect (not all secondary setaerepresented); (36–37) prothoracic leg; (36) anterior aspect; (37) posterior aspect; (38) abdominal segment eight, dorsalaspect; (39) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 40–44. Rhantus calidus (first-instar larva): (40) head capsule, dorsal aspect (colour pattern not represented);(41–42) metathoracic leg; (41) anterior aspect; (42) posterior aspect; (43) abdominal segment eight, dorsal aspect; (44)urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur; FR, frontoclypeus;PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter; UR, urogomphus. Numbers and lowercase letters referto primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.20 mm.



FIGURES 45–50. Rhantus calidus (third-instar larva): (45) head capsule, dorsal aspect (not all secondary setaerepresented); (46) antenna, dorsal aspect; (47–48) prothoracic leg; (47) anterior aspect; (48) posterior aspect; (49)abdominal segment eight, dorsal aspect; (50) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 51–55. Rhantus calileguai (first-instar larva): (51) head capsule, dorsal aspect (colour pattern notrepresented); (52–53) metathoracic leg; (52) anterior aspect; (53) posterior aspect; (54) abdominal segment eight, dorsalaspect; (55) urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur; FR,frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.15mm.



FIGURES 56–60. Rhantus calileguai (third-instar larva): (56) head capsule, dorsal aspect (not all secondary setaerepresented); (57–58) prothoracic leg; (57) anterior aspect; (58) posterior aspect; (59) abdominal segment eight, dorsalaspect; (60) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 61–65. Rhantus capensis (third-instar larva): (61) head capsule, dorsal aspect (not all secondary setaerepresented); (62–63) prothoracic leg; (62) anterior aspect; (63) posterior aspect; (64) abdominal segment eight, dorsalaspect; (65) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 66–70. Rhantus consputus (first-instar larva): (66) head capsule, dorsal aspect (colour pattern notrepresented); (67–68) metathoracic leg; (67) anterior aspect; (68) posterior aspect; (69) abdominal segment eight, dorsalaspect; (70) urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur; FR,frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter; UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.20mm.



FIGURES 71–75. Rhantus consputus (third-instar larva): (71) head capsule, dorsal aspect (not all secondary setaerepresented); (72–73) prothoracic leg; (72) anterior aspect; (73) posterior aspect; (74) abdominal segment eight, dorsalaspect; (75) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 76–80. Rhantus exsoletus (first-instar larva): (76) head capsule, dorsal aspect (colour pattern notrepresented); (77–78) metathoracic leg; (77) anterior aspect; (78) posterior aspect; (79) abdominal segment eight, dorsalaspect; (80) urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur; FR,frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia: TR, trochanter; UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.20mm.



FIGURES 81–85. Rhantus exsoletus (third-instar larva): (81) head capsule, dorsal aspect (not all secondary setaerepresented); (82–83) prothoracic leg; (82) anterior aspect; (83) posterior aspect; (84) abdominal segment eight, dorsalaspect; (85) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 86–90. Rhantus fennicus (first-instar larva): (86) head capsule, dorsal aspect (colour pattern not represented);(87–88) metathoracic leg; (87) anterior aspect; (88) posterior aspect; (89) abdominal segment eight, dorsal aspect; (90)urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur; FR, frontoclypeus;PA, parietale; PT, pretarsus; TA, tarsus, TI, tibia: TR, trochanter; UR, urogomphus. Numbers and lowercase letters referto primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.20 mm.



FIGURES 91–95. Rhantus fennicus (third-instar larva): (91) head capsule, dorsal aspect (not all secondary setaerepresented); (92–93) prothoracic leg; (92) anterior aspect; (93) posterior aspect; (94) abdominal segment eight, dorsalaspect; (95) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 96–100. Rhantus frontalis (third-instar larva): (96) head capsule, dorsal aspect (not all secondary setaerepresented); (97–98) prothoracic leg; (97) anterior aspect; (98) posterior aspect; (99) abdominal segment eight, dorsalaspect; (100) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 101–106. Rhantus grapii (first-instar larva): (101) head capsule, dorsal aspect (colour pattern notrepresented); (102) maxilla, ventral aspect; (103–104) metathoracic leg; (103) anterior aspect; (104) posterior aspect;(105) abdominal segment eight, dorsal aspect; (106) urogomphus, dorsal aspect. AB, abdominal segment eight; CO,coxa; EB, egg bursters; FE, femur; FR, frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter;UR, urogomphus. Numbers and lowercase letters refer to primary setae and pores, respectively; filled squares refer toadditional setae. Scale bars = 0.20 mm.



FIGURES 107–111. Rhantus grapii (third-instar larva): (107) head capsule, dorsal aspect (not all secondary setaerepresented); (108–109) prothoracic leg; (108) anterior aspect; (109) posterior aspect; (110) abdominal segment eight,dorsal aspect; (111) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 112–116. Rhantus latitans (third-instar larva): (112) head capsule, dorsal aspect (not all secondary setaerepresented); (113–114) prothoracic leg; (113) anterior aspect; (114) posterior aspect; (115) abdominal segment eight,dorsal aspect; (116) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 117–121. Rhantus notaticollis (first-instar larva): (117) head capsule, dorsal aspect (colour pattern notrepresented); (118–119) metathoracic leg; (118) anterior aspect; (119) posterior aspect; (120) abdominal segment eight,dorsal aspect; (121) urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur;FR, frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter; UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.20mm.



FIGURES 122–126. Rhantus notaticollis (third-instar larva): (122) head capsule, dorsal aspect (not all secondary setaerepresented); (123–124) prothoracic leg; (123) anterior aspect; (124) posterior aspect; (125) abdominal segment eight,dorsal aspect; (126) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 127–131. Rhantus orbignyi (first-instar larva): (127) head capsule, dorsal aspect (colour pattern notrepresented); (128–129) metathoracic leg; (128) anterior aspect; (129) posterior aspect; (130) abdominal segment eight,dorsal aspect; (131) urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur;FR, frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter; UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.15mm (Fig. 127) and 0.20 mm.



FIGURES 132–136. Rhantus orbignyi (third-instar larva): (132) head capsule, dorsal aspect (not all secondary setaerepresented); (133–134) prothoracic leg; (133) anterior aspect; (134) posterior aspect; (135) abdominal segment eight,dorsal aspect; (136) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 137–141. Rhantus phocaenarum (first-instar larva): (137) head capsule, dorsal aspect (colour pattern notrepresented); (138–139) metathoracic leg; (138) anterior aspect; (139) posterior aspect; (140) abdominal segment eight,dorsal aspect; (141) urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa: EB, egg bursters; FE, femur;FR, frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter; UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.20mm.



FIGURES 142–146. Rhantus phocaenarum (third-instar larva): (142) head capsule, dorsal aspect (not all secondarysetae represented); (143–144) prothoracic leg; (143) anterior aspect; (144) posterior aspect; (145) abdominal segmenteight, dorsal aspect; (146) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 147–151. Rhantus signatus (first-instar larva): (147) head capsule, dorsal aspect (colour pattern notrepresented); (148–149) metathoracic leg; (148) anterior aspect; (149) posterior aspect; (150) abdominal segment eight,dorsal aspect; (151) urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur;FR, frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter; UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.15mm.



FIGURES 152–156. Rhantus signatus (third-instar larva): (152) head capsule, dorsal aspect (not all secondary setaerepresented); (153–154) prothoracic leg; (153) anterior aspect; (154) posterior aspect; (155) abdominal segment eight,dorsal aspect; (156) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 157–161. Rhantus simulans (third-instar larva): (157) head capsule, dorsal aspect (not all secondary setaerepresented); (158–159) prothoracic leg; (158) anterior aspect; (159) posterior aspect; (160) abdominal segment eight,dorsal aspect; (161) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 162–166. Rhantus socialis (first-instar larva): (162) head capsule, dorsal aspect (colour pattern notrepresented); (163–164) metathoracic leg; (163) anterior aspect; (164) posterior aspect; (165) abdominal segment eight,dorsal aspect; (166) urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur;FR, frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus, TI, tibia; TR, trochanter; UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.20mm.



FIGURES 167–171. Rhantus socialis (third-instar larva): (167) head capsule, dorsal aspect (not all secondary setaerepresented); (168–169) prothoracic leg; (168) anterior aspect; (169) posterior aspect; (170) abdominal segment eight,dorsal aspect; (171) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 172–176. Rhantus suturalis (third-instar larva): (172) head capsule, dorsal aspect (not all secondary setaerepresented); (173–174) prothoracic leg; (173) anterior aspect; (174) posterior aspect; (175) abdominal segment eight,dorsal aspect; (176) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 177–181. Rhantus suturellus (first-instar larva): (177) head capsule, dorsal aspect (colour pattern notrepresented); (178–179) metathoracic leg; (178) anterior aspect; (179) posterior aspect; (180) abdominal segment eight,dorsal aspect; (181) urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur;FR, frontoclypeus; PA, parietale; PT, pretarsus, TA, tarsus; TI, tibia; TR, trochanter; UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.20mm.



FIGURES 182–186. Rhantus suturellus (third-instar larva): (182) head capsule, dorsal aspect (not all secondary setaerepresented); (183–184) prothoracic leg; (183) anterior aspect; (184) posterior aspect; (185) abdominal segment eight,dorsal aspect; (186) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURES 187–191. Rhantus validus (first-instar larva): (187) head capsule, dorsal aspect (colour pattern notrepresented); (188–189) metathoracic leg; (188) anterior aspect; (189) posterior aspect; (190) abdominal segment eight,dorsal aspect; (191) urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur;FR, frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter; UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares and triangles refer to additional setae andpores, respectively. Scale bars = 0.20 mm.



FIGURES 192–195. Rhantus validus, (first-instar larva), head appendages: (192–193) maxilla; (192) dorsal aspect;(193) ventral aspect; (194–195) labium; (194) dorsal aspect; (195) ventral aspect. LA, labium; MX, maxilla. Numbersand lowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars =0.10 mm.



FIGURES 196–200. Rhantus validus (third-instar larva): (196) head capsule, dorsal aspect (not all secondary setaerepresented); (197–198) prothoracic leg; (197) anterior aspect; (198) posterior aspect; (199) abdominal segment eight,dorsal aspect; (200) urogomphus, dorsal aspect. Scale bars = 0.60 mm.



FIGURES 201–205. Rhantus wallisi (first-instar larva): (201) head capsule, dorsal aspect (colour pattern notrepresented); (202–203) metathoracic leg; (202) anterior aspect; (203) posterior aspect; (204) abdominal segment eight,dorsal aspect; (205) urogomphus, dorsal aspect. AB, abdominal segment eight; CO, coxa; EB, egg bursters; FE, femur;FR, frontoclypeus; PA, parietale; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter; UR, urogomphus. Numbers andlowercase letters refer to primary setae and pores, respectively; filled squares refer to additional setae. Scale bars = 0.20mm.



FIGURES 206–210. Rhantus wallisi (third-instar larva): (206) head capsule, dorsal aspect (not all secondary setaerepresented); (207–208) prothoracic leg; (207) anterior aspect; (208) posterior aspect; (209) abdominal segment eight,dorsal aspect; (210) urogomphus, dorsal aspect. Scale bars = 0.50 mm.



FIGURE 211. Strict consensus tree of 4800 most parsimonious trees reconstructed (43 informative characters of 35taxa). Bremer support values are indicated above branches; jackknife values are indicated below branches.



FIGURE 212. Strict consensus tree of 1400 most parsimonious trees reconstructed using implied weighting (43informative characters of 35 taxa). Bremer support values are indicated above branches; jackknife values are indicatedbelow branches.


Documents

Zootaxa, Larval morphology of Rhantus Dejean, 1833ocean.otr.usm.edu/~w777157/Dytiscid symposium/Rhantus.pdf · Larval morphology of Rhantus Dejean, 1833 (Coleoptera: Dytiscidae: Colymbetinae):