Rheotanytarsus Thienemann et Bause (Diptera: Chironomidae) from Central America and Mexico

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Rheotanytarsus Thienemann et Bause (Diptera:Chironomidae) from Central America and MexicoRosina Abena Kwatemaa Kyerematen & Trond AndersenPublished online: 09 Aug 2010.

To cite this article: Rosina Abena Kwatemaa Kyerematen & Trond Andersen (2002) Rheotanytarsus Thienemann et Bause(Diptera: Chironomidae) from Central America and Mexico, Studies on Neotropical Fauna and Environment, 37:1, 23-51

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Abstract

Eleven new species of Rheotanytarsus Thienemann et Bause from Central America and Mexico are described: R.baculus sp. n., R. calacmulensis sp. n., R. foliatus sp. n., R. guanacastensis sp. n., R. hanseni sp. n., R. kusii sp. n., R.nuamae sp. n., R. scutulatus sp. n., R. subtilis sp. n., and R. thunesi sp. n. as males only and R. ramirezae sp. n. as maleand pupae. Two species are redescribed: R. exiguus(Johannsen) as male, pupae and larvae; and R. meridionalis(Johannsen) as male only. Keys to males and known pupaeof Central American and Mexican Rheotanytarsus are given.

Keywords: Chironomidae, Rheotanytarsus, new species,redescription, neotropical, Costa Rica, Mexico.

Introduction

Including the species described below a total of 94 speciesof the genus Rheotanytarsus Thienemann et Bause in Bause,1913 are known from all zoogeographical regions except the Antarctic (Sæther & Kyerematen, 2001). The genusappears to be particularly rich both in number of species and individuals in tropical rain forests (Cranston, 1997). Thelarvae of Rheotanytarsus are filter feeders, using nets sus-pended between arms at the anterior end of their cases(Pinder & Reiss, 1983). They live in moderately fast to mod-erately slow flowing rivers, and in streams, creeks and ponds.R. ceratophylli (Dejoux, 1973) and, apparently, all larvae ofthe ceratophylli group, however, live in temporary stagnantwaters (Dejoux, 1973).

In their catalogue of the Neotropical and Mexican chi-ronomids, Spies and Reiss (1996) list six species from theneotropical region, of which three occur in Central America:R. exiguus (Johannsen, 1905), described by Johannsen

(1905) from USA, is recorded from St. Croix in theCaribbean (Curry & Curry, 1971). R. meridionalis(Johannsen, 1938), described by Johannsen (1938) fromPuerto Rico, is known only from the type locality. R. hamatusSublette et Sasa, 1994 was described by Sublette and Sasa(1994) from Guatemala and has also been recorded fromArizona (Sublette et al., 1998). Recently R. contrerasi Ander-sen et Sæther, 2000 was described from Mexico (Kyerematenet al., 2000). In the present paper an additional eleven newspecies from Mexico and Costa Rica are described. Further,two of the described species, R. exiguus and R. meridionalisare redescribed.

Materials and methods

The general terminology and morphology follows Sæther(1980), with the additions given in Sæther (1990). The countsof setae on the wing veins include both dorsal and ventralsetae, and setae which stand at the margin of a vein areregarded as belonging to the vein. The broad flattened setaeof the pupal exuviae are called taenia(e), following Langton(1994). The measurements are given as ranges followed by amean when four or more measurements are made, and by thenumbers of individuals (n) in parentheses. The male hypopy-gium is figured with anal point and tergite IX removed;dorsal aspect to the left, ventral aspect to the right. Dorsalview of tergite IX, anal point, superior and inferior volsellaand gonocoxite and gonostylus are figured separately, as arethe superior and the median volsella.

Material examined

Types and other material of the described species examinedare borrowed from Cornell University Insect Collection, New

Received: 5 April 2000Accepted: 27 May 2001

Correspondence: T. Andersen, Museum of Zoology, University of Bergen, Muséplass 3, N-5007 Bergen, Norway. Fax: +47 55589677. E-mail: [email protected]

Rheotanytarsus Thienemann et Bause (Diptera: Chironomidae)

from Central America and Mexico

Rosina Abena Kwatemaa Kyerematen1 and Trond Andersen2

1Department of Zoology, University of Ghana, Legon, Ghana2Museum of Zoology, University of Bergen, Bergen, Norway

Studies on Neotropical Fauna and Environment 0165-0521/02/3701-023$16.002002, Vol. 37, No. 1, pp. 23–51 © Swets & Zeitlinger

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https://www.researchgate.net/publication/248899856_Revision_of_Australian_Rheotanytarsus_Thienemann_Bause_Diptera_Chironomidae_with_emphasis_on_immature_stages?el=1_x_8&enrichId=rgreq-39ab170b-52dc-4750-a8e2-0d3f93dce206&enrichSource=Y292ZXJQYWdlOzIzMzI1NDc3MjtBUzoxMDM3OTI5Mzg4NDgyNTdAMTQwMTc1NzU3MzI1MA==

https://www.researchgate.net/publication/262087402_Chironomidae_Diptera_of_the_Colorado_River_Grand_Canyon_Arizona_USA_I_Systematics_and_ecology?el=1_x_8&enrichId=rgreq-39ab170b-52dc-4750-a8e2-0d3f93dce206&enrichSource=Y292ZXJQYWdlOzIzMzI1NDc3MjtBUzoxMDM3OTI5Mzg4NDgyNTdAMTQwMTc1NzU3MzI1MA==

https://www.researchgate.net/publication/32995896_Contribution_a_l'etude_des_chironomides_du_Tchad_Description_de_TANYTARSUS_RHEOTANYTARSUS_CERATOPHYLLI_n_sp_6eme_note?el=1_x_8&enrichId=rgreq-39ab170b-52dc-4750-a8e2-0d3f93dce206&enrichSource=Y292ZXJQYWdlOzIzMzI1NDc3MjtBUzoxMDM3OTI5Mzg4NDgyNTdAMTQwMTc1NzU3MzI1MA==

https://www.researchgate.net/publication/32995896_Contribution_a_l'etude_des_chironomides_du_Tchad_Description_de_TANYTARSUS_RHEOTANYTARSUS_CERATOPHYLLI_n_sp_6eme_note?el=1_x_8&enrichId=rgreq-39ab170b-52dc-4750-a8e2-0d3f93dce206&enrichSource=Y292ZXJQYWdlOzIzMzI1NDc3MjtBUzoxMDM3OTI5Mzg4NDgyNTdAMTQwMTc1NzU3MzI1MA==

https://www.researchgate.net/publication/238457126_THE_CHIRONOMIDAE_DIPTERA_FOUND_IN_THE_US_VIRGIN_ISLANDS_ANEGADA_BRITISH_VIRGIN_ISLANDS?el=1_x_8&enrichId=rgreq-39ab170b-52dc-4750-a8e2-0d3f93dce206&enrichSource=Y292ZXJQYWdlOzIzMzI1NDc3MjtBUzoxMDM3OTI5Mzg4NDgyNTdAMTQwMTc1NzU3MzI1MA==

24 R.A.K. Kyerematen and T. Andersen

York, USA (CUC); and from the collection of James E. Sub-lette, Tucson, Arizona, USA (JES). Much of this materialconsists of uncleared full mounts and it was not possible toobserve details such as the tentorium and stipes in all of thespecimens. Several measurements given for these speciesmight therefore be slightly doubtful.

The holotype and three paratypes of R. calakmulensissp. n. are deposited in the Instituto de Ecologia, A. C.,Xalapa, Veracruz, Mexico (IEXA), while the remainingparatypes of this species are in the Museum of Zoology, Uni-versity of Bergen, Norway (ZMBN). For the remaining newlydescribed species the holotypes are all deposited in ZMBN.The first paratype of the Mexican species, if any, is in IEXA,while the remaining paratypes and other material are inZMBN.

Results

Genus Rheotanytarsus Thienemann et Bause

Rheotanytarsus Thienemann et Bause in Bause 1913: 120.Syntanytarsus (Rheotanytarsus) Thienemann et Bause, in Bause

1913: 120.Tanytarsus (Rheotanytarsus) auct.Rheotanytarsus Thienemann et Bause, Fittkau 1960: 397.

Type species

Tanytarsus pentapoda Kieffer, 1909, by subsequent designa-tion of Goetghebuer (1954: 132).

Diagnosis

As in Pinder and Reiss (1983, 1986), Cranston et al. (1989),Sæther (1977) and Sæther and Kyerematen (2001).

Systematics

Using different parsimony analyses Sæther and Kyerematen(2001) recently divided Rheotanytarsus into more or less distinctive species groups. However, adults and immatures ofmany species remain to be associated and the placement ofseveral species based on imagines only is doubtful. Of the 18species groups suggested the following have representativesin Central America and Mexico: the muscicola group, thepentapoda group, the exiguus group, the acerbus group, thepellucidus group, the calakmulensis group, the trivittatusgroup, the thermae group and the phaselus group.

Key to male imagines of Rheotanytarsus Thienemann etBause from Central America and Mexico

1. Median volsella long, extending beyond apex of inferiorvolsella . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

– Median volsella shorter, not extending beyond apex ofinferior volsella . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32. Median volsella reaching just beyond apex of inferiorvolsella, with distal setae fused into rounded plates withapical points. Anal point with second smaller crest near apex.Mexico (Figs. 67–73) . . . . . . . . . . . . . . R. hanseni sp. n.– Median volsella reaching beyond apex of gonostylus, withdistal lamelliform setae not fused into plate; anal point crestopen and V-shaped. Mexico (Kyerematen et al., 2000, Figs.53–56). . . . . . . . . . . . . . R. contrerasi Andersen et Sæther3. Median volsella extending well beyond apex of superiorvolsella . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4– Median volsella reaching apex of superior volsella, orshorter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64. Superior volsella rounded; anal tergite with V-shapedbands only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5– Superior volsella subtriangular, with posterior margin produced giving a knob-like projection; anal tergite with weak, basal tergite band not joined medially, and two-branched, open V-shaped bands. Costa Rica, Mexico (Figs.39–45) . . . . . . . . . . . . . . . . . . . . . . . . . . R. foliatus sp. n.5. Anal tergite with V-shaped bands joined medially; AR0.67–0.72. Mexico (Figs. 32–38). . R. calakmulensis sp. n.– Anal tergite with open V-shaped bands; AR 0.13–0.15.Costa Rica (Figs. 8–14) . . . . . . . . . . . . . R. baculus sp. n.6. Apex of anal point parallel-sided . . . . . . . . . . . . . . . . 7– Apex of anal point distinctly spatulate . . . . . . . . . . . . 87. Superior volsella subtriangular, with narrowly rounded posterior corner; mid and hind tibia lacking spurs; AR 0.62–0.66. USA, St. Croix (Figs. 15–18). . . . . . . . . . . . . . . . . . . . . . . . . . . R. exiguus (Johannsen)– Superior volsella subquadrate, with broadly rounded pos-terior corner; mid and hind tibia each with two spurs; ARabout 0.46. Mexico (Figs. 46–52). . . . . . . . . R. kusii sp. n.8. Median volsella with distal, lamelliform setae, but lackingplate(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9– Median volsella with distal setae fused into plate(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109. Superior volsella subtriangular; median volsella with distal lamelliform setae curved, pointing mesad; AR 0.66–0.70. Costa Rica (Figs. 1–7). . . . R. thunesi sp. n.– Superior volsella rounded; median volsella with distallamelliform setae straight, pointing caudad; AR about 0.34.Guatemala, USA (Sublette & Sasa, 1994, Fig. 188). . . . . . . . . . . . . . . . . . . . . . . R. hamatus Sublette et Sasa10. Superior volsella rounded; AR > 0.40 . . . . . . . . . . . 11– Superior volsella subtriangular; AR < 0.40 . . . . . . . . 1211. Median volsella basally with strong, lamelliform setae pointing caudad; AR about 0.51. Mexico (Figs. 53–59). . . . . . . . . . . . . . . . . . . . . . . . . . . . . R. nuamae sp. n.– Median volsella without strong, basal, lamelliform setae; AR about 0.42. Puerto Rico (Figs. 19–22). . . . . . . . . . . . . . . . . . . . . . . R. meridionalis (Johannsen)12. Anal tergite with basal tergite band, fused or open, inaddition to V-shaped bands; inferior volsella with narrowlyrounded apex; gonostylus gradually tapering apically; AR0.30–0.39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

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Central American and Mexican Rheotanytarsus 25

– Anal tergite with V-shaped bands only; inferior volsellawith broad, subrectangular apex; gonostylus more or less parallel-sided apically; AR 0.21–0.24. Costa Rica (Figs.60–66). . . . . . . . . . . . . . . . . . . . . . . . R. scutulatus sp. n.13. Anal tergite with open basal tergite band, in addition toV-shaped bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14– Anal tergite with basal tergite band fused medially, in addition to V-shaped bands. Costa Rica (Figs. 91–97). . . . . . . . . . . . . . . . . . . . . . . . . . R. subtilis sp. n.14. Superior volsella with bluntly triangular posterior extension; median volsella L-shaped. Costa Rica (Figs. 74–80). . . . . . . . . . . . . . . . . . . . R. guanacastensis sp. n.– Superior volsella without posterior extension; median volsella sinuous. Mexico (Figs. 81–86). . . . . . . . . . . . . . . . . . . . . . . . . . . R. ramirezae sp. n.

Key to known pupae of Rheotanytarsus Thienemann etBause from Central America and Mexico

1. Tergite II–V or II–VI with anterior patches of spinules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2– Tergites II–IV with anterior patches of spin-ules. . . . . . . . . . . . . . . . R. contrerasi Andersen et Sæther2. Tergite II–V with paired anterior patches of spinules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3– Tergite II–VI with paired anterior patches of spinules.(Figs. 23–26). . . . . . . . . . . . . . . . R. exiguus (Johannsen)3. Tergite II with less than 30 hooklets.. . . . . . . . . . . . . . . . . . . . . . . R. hamatus Sublette et Sasa– Tergite II with more than 30 hooklets. (Figs. 87–90). . . . . . . . . . . . . . . . . . . . . . . . . . . R. ramirezae sp. n.

Species account

The muscicola group

The group comprises four species from the Palaearctic andNeotropical zoogeographical regions. The only known pupais characterised by having a thoracic horn with median bendand points in apical half, tergites II–V with circular anteriorspine patches, posterior shagreen patch on tergite II notdivided, and anal lobe without dorsal seta.

The male imagines have basal tergite bands, and stronglydeveloped V-shaped bands, anal point with V-shaped to shortrounded crest, superior volsella with slightly hooked or knob-like posterior extension, median volsella not reaching apexof superior volsella, with apical setae usually fused into platewith points, and gonostylus abruptly tapered in apicalportion.

Rheotanytarsus thunesi sp. n. (Figs. 1–7)

Type material

Holotype �: Costa Rica, Heredia Province, La Selva Bio-logical Station, 10°26¢N 83°59¢W, 150m a.s.l., at light,16.VIII.1994, K. Thunes (ZMBN Type No. 335). Paratypes:

2 �� as holotype; 1 � as holotype except 2.III.1993; 1 �as holotype except 10°26¢N 84°01¢W, black light (ZMBN).

Etymology

Named after Dr. Karl Thunes, who collected the material.

Description

Male imago (n = 5, except when otherwise stated). Totallength 2.00–2.14, 2.08mm. Wing length 1.20–1.32, 1.26mm.Total length/wing length 1.62–1.67, 1.64. Wing length/lengthof profemur 1.69–1.81, 1.74. Thorax, abdomen and legs pale.

Head (Fig. 1). AR 0.66–0.70, 0.68. Thirteenth flagellom-ere 328–368, 347 mm long. Temporal setae 6–7, 6; including2–3, 3 inner verticals; 2 outer verticals; and 1–2, 1 postor-bitals. Clypeus with 10–16, 13 setae. Tentorium 60–80, 72mm long; 14–16, 14 mm wide at sieve pore and 8–10, 9mm wide at posterior tentorial pit. Stipes 70–94, 88 mmlong; 12–20, 16mm wide. Length of palpomeres (in mm):24–28, 26; 24–28, 26; 66–76, 70; 76–80, 78; 140–160, 150(4). Fifth palpomere/third palpomere 2.09–2.23, 2.13 (4).

Thorax (Fig. 2). Dorsocentrals 5–7, 6; acrostichals 10–16,13. Scutellum with 4–6, 5 setae.

Wing (Fig. 3). VR 1.41–1.56, 1.49. Brachiolum with 1 seta;R with 15–18, 16; R1 with 20–26, 22; R4+5 with 41–51, 45setae. Sc bare. M with 0–2, 1 setae; RM with 1–2, 2; M1+2 with47–64, 56; M3+4 with 25–33, 27; Cu with 12–17, 14; Cu1 with14–21, 16; PCu with 42–51, 46; and An with 18–23, 21 setae.Cells m with 8 setae, r4+5 with about 300, m1+2 with about 270,m3+4 with about 85, cu with 30 and an with 22 setae.

Legs (Table 1). Spur of front tibia 12–16, 15 mm long,spurs of middle tibia 8–10 (3) and 12–18 (3) mm long; ofhind tibia 14–18, 16 and 18–20, 18mm long, all excludingcomb. Comb of middle tibia 10–12, 11 (4) mm long, of hindtibia 12–14, 13 mm long. Width at apex of front tibia 34–38,35mm, of middle tibia 32 (4) mm; of hind tibia 34–36, 35mm.

Hypopygium (Figs. 4, 5). Anal tergite with basal tergiteband and medially fused V-shaped bands. Tergite IX with8–11, 10 setae. Anal point 48–64, 56mm long; 14–22, 19mmwide at base; 6–8, 7 mm at apex. Crest well developed and V-shaped with 3 (4) setae between anal tergites bands. Laterosternite IX with 1 setae. Phallapodeme 54–62, 56mmlong; transverse sternapodeme 16–22, 18 (4) mm long. Gono-coxite 80–84, 82mm long; gonostylus 78–88, 84mm long.Superior volsella (Fig. 6) 34–42, 38mm long, subtriangular,with microtrichia, and with 4 dorsal setae in addition to 2 marginal. Inferior volsella 58–66, 61 mm long, withmicrotrichia dorsally, and with 10–12, 11 setae apically.Median volsella (Fig. 7) 30–42, 36 mm long, with lamelli-form setae not fused into a plate. HR 0.91–1.08, 0.97; HV2.27–2.74, 2.46.

Diagnostic characters

R. thunesi sp. n. can be separated from all other Neotropicalspecies on the short, curved median volsella with subulateapical setae not fused into plate.

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Figs. 1–7. Rheotanytarsus thunesi sp. n., male imago: (1) head; (2) thorax; (3) wing; (4) anal point and dorsal aspect of left gonocoxite andgonostylus; (5) hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect; (6) superior volsella; (7) medianvolsella.

Distribution and biology

The species is known only from Costa Rica. The specimenswere taken in a lowland rainforest close to a rather slowflowing river.

The pentapoda group

The group comprises 7 species from the Afrotropical, Oriental, Neotropical and Palaearctic zoogeographicalregions. The pupae have tergites II–VI with paired, anterior

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circular spine patches, tergite II bare or with posterior sha-green not arranged in two patches, and anal lobe withoutdorsal seta.

The male imagines have basal anal tergite bands and V-shaped bands, spatulate or narrow and tapering anal pointwith V-shaped and open crest, median volsella extendingbeyond superior volsella, but not reaching apex of inferiorvolsella and with apical plates, and in most species thegonostylus is abruptly tapered without parallel-sided apicalportion.

Rheotanytarsus baculus sp. n. (Figs. 8–14)

Type material

Holotype �: Costa Rica, Guanacaste Province, GuanacasteConservation Area, Cerro Cacao, Rio San Josecito, 1000ma.s.l., Malaise trap, 3–7.V.1993, T. Andersen (ZMBN TypeNo. 336). Paratype: 1 � as holotype (ZMBN).

Etymology

After the Latin baculum meaning club; referring to the club-shaped median volsella, using the suffix -us denoting thegender of the genus.

Description

Male imago (n = 2). Total length 1.58–1.66 mm. Wing length0.94–1.01mm. Total length/wing length 1.65–1.67. Winglength/length of profemur 2.03–2.21. Thorax, abdomen andlegs dark brown.

Head (Fig. 8). AR 0.13–0.15. Thirteenth flagellomere 50–58mm long. Temporal setae 7–8; including 3 inner verticals,2–3 outer verticals, and 2 postorbitals. Clypeus with 16–17setae. Tentorium 70–76 mm long, 12–18 mm wide at sievepore, 8mm wide at posterior tentorial pit. Stipes 80–90mmlong, 16–20mm wide. Length of palpomeres (in mm): 22–24,22–24, 44, 54–58, 120–130. Fifth palpomere/third palpomere2.73–2.95.

Thorax (Fig. 9). Dorsocentrals 10, acrostichals 14–18.Scutellum with 3 setae.

Wing (Fig. 10). VR 1.50–1.52. Brachiolum with 1 seta, Rwith 13–14, R1 with 17–18, R4+5 with 42–43 setae. Sc and M

bare. RM with 2 setae, M1+2 with 42–44, M3+4 with 18–21,Cu with 11–13, Cu1 with 11–12, PCu with 37–40 and Anwith 19–20 setae. Cells m with 5 setae, r4+5 with about 220,m1+2 with about 170, m3+4 with 80, cu with 30 and an with25 setae.

Legs (Table 2). Spur of front tibia 12–14 mm long, spurs of middle tibia 10 and 14–18 mm long, of hind tibia 14–16and 18mm long, all excluding comb. Comb of middle tibia 10mm long, of hind tibia 12mm long. Width at apex offront tibia 34 mm, of middle tibia 30–32 mm, of hind tibia 36mm.

Hypopygium (Figs. 11, 12). Anal tergite with open, V-shaped bands. Tergite IX with 6–7 setae. Anal point 50–52mm long, 18–20mm wide at base, 6mm wide at apex. Crestwell developed and V-shaped with 4 setae in between analtergite bands. Laterosternite IX with 1 setae. Phallapodeme60–62mm long, transverse sternapodeme 20–24 mm long.Gonocoxite 72–74mm long, gonostylus 60mm long. Superiorvolsella (Fig. 13) 26–30mm long, rounded, with 4–5 dorsalsetae in addition to 2 marginal. Inferior volsella 56–58mmlong, with 10–12 setae apically. Median volsella (Fig. 14)44–48mm long, with lamelliform setae fused into platewithout apical points. HR 1.20–1.23, HV 2.63–2.77.


R. baculus sp. n. can be separated from other Neotropicalspecies by its small size, low antennal ratio, and dark colour.


The species is known only from the Guanacaste Conserva-tion Area in Costa Rica, where it was taken close to a small,fast flowing stream with substrate of stones and gravel.

The exiguus group

The pupa of this monotypic group has anteriorly rugulosefrontal plate with frontal setae, thoracic horn with spinulesin apical 1/3–1/4, tergites II–VI with paired anterior circularpatches of spines, tergite II with posterior shagreen patch notdivided, caudal hooklets of tergite II occupying at leastmedian half, and anal lobe with hair-like dorsal seta.

Table 1. Lengths (in mm) and proportions of legs of Rheotanytarsus thunesi sp. n.

fe ti ta1 ta2 ta3 ta4 ta5 LR BV SV BR

p1 688–780 240–312 900–952 424–444 308–324 240 (1) 96 (1) 3.17–3.21 1.80 (1) 1.09–1.11 –725 282 (2) (2) (2) (2) (2)

p2 656–672 476–512 268–284 124–132 92–96 48–60 40–48 0.53–0.58 4.25–4.68 4.03–4.39 5.5–6.5671 (4) 496 (4) 276 (4) 128 (4) 93 (4) 55 (4) 44 (4) 0.56 (4) 4.51 (4) 4.23 (4) 6.0 (4)

p3 668–740 548–592 300–324 212–224 180–200 104–116 56–64 0.52–0.57 2.68–2.82 3.96–4.31 5.2–6.0711 571 311 (4) 218 (4) 188 (4) 111 (4) 59 (4) 0.55 (4) 2.75 (4) 4.09 (4) (2)

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Figs. 8–14. Rheotanytarsus baculus sp. n., male imago: (8) head; (9) thorax; (10) wing; (11) anal point and dorsal aspect of left gonocox-ite and gonostylus; (12) hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect; (13) superior volsella;(14) median volsella.

Table 2. Lengths (in mm) and proportions of legs of Rheotanytarsus baculus sp. n.


p1 456–464 232–240 592 280 208 16 80 2.55 1.77 1.18 –p2 488–496 336–360 208 96–128 72 40–48 32 0.58–0.62 3.77–4.33 4.00–4.08 4.6–5.1p3 520–536 432 280–288 152–160 144 88 56 0.65–0.67 2.75–2.85 3.36–3.40 4.5

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The male imago lacks spurs on mid and hind tibia, analtergite bands V-shaped with 4–5 setae between bands, analpoint parallel-sided with V-shaped and basally open crest,and superior volsella with knob-like, triangular extension.

Rheotanytarsus exiguus (Johannsen)(Figs. 15–18, 23–31)

Tanytarsus exiguus Johannsen, 1905: 249Rheotanytarsus exiguus (Johannsen); Spies and Reiss, 1996:

73

Material examined

USA, New Mexico, Eddy County, Pecos River, HarrounCrossing, Mid Channel riffle rubble, 1 mature � pupa4.I.1980, M. Beard; 1 larva as above; 1 mature � pupa andlarva as above except Cladophora and sedge at shoreline ofriffle; 1 � as above except Surber 1,552, 30.III.1979; 1 � asabove except below Brantly Res., T20S, R26E, S27,13.VI.1991; New Mexico, San Miguel Co., Canadian R. nearSabinoso, T17N, R24E, S34, UV sample, 1 � 17.VI.1992,Harch & Jacobi (all JES).

Redescription

Male imago (n = 4, except when otherwise stated). Totallength 2.72–3.10 (2) mm. Wing length 1.37–1.48 (2) mm.Total length/wing length 1.98 (1). Wing length/length of pro-femur 2.12 (1). Thorax light brown, abdomen pale, legs pale.

Head. AR 0.62–0.66 (2). Thirteenth flagellomere284–316 (2) mm long. Temporal setae 8–10 (3), including3–4 (3) inner verticals, 2–3 (3) outer verticals and 2–3 (3)postorbitals. Clypeus with 18–20 (3) setae. Tentorium90–120, 103 mm long; 20–38, 28 mm wide at sieve pore and 8–12, 9 mm wide at posterior tentorial pit. Stipes 70–112(2) mm long, 18–20mm wide. Palpomeres length (in mm):20–26 (2), 28 (2), 80–96 (2), 80–106 (2), 170 (1). Fifth palpal segment/third palpal segment 1.77 (1).

Thorax. Dorsocentrals 10–11, 10; acrostichals 18–20, 20.Scutellum with 4–5, 4 setae.

Wing. VR 1.43 (1). Brachiolum with 1 seta, R with 22 (1)setae, R1 with 32 (1), R4+5 with 57 (1). Sc and M bare. RMwith 1 (1) setae, M1+2 with 44 (1), M3+4 with 32 (1), Cu with16 (1), Cu1 with 21 (1), PCu with 54 (1), and An with 35 (1)setae. Cells m with 5 setae, r4+5 with about 200, m1+2 withabout 200, m3+4 with about 70, cu with about 40 and an withabout 60 setae.

Legs (Table 3). Spurs of front tibia 14 (2) mm long, middleand hind tibia without spurs. Comb of middle tibia 12–14 (2)mm long, of hind tibia 12–14 (2) mm long. Width at apex offront tibia 38–42 (2) mm, of middle tibia 38–40 (2) mm, ofhind tibia 44–46 (2) mm.

Hypopygium (Figs. 15, 16). Anal tergite with open, V-shaped bands. Tergite IX with 4–7 (3) setae. Anal point56–72, 64mm long; 14–20, 17 mm wide at base; 8mm at apex.

Crests open and V-shaped with 4–5, 4 setae between analtergite bands. Phallapodeme 76–86, 79 mm long; transversesternapodeme 32–50, 39 mm long. Gonocoxite 110–128, 117mm long; gonostylus 106–126, 113mm long. Superiorvolsella (Fig. 17) 34–40, 38mm long, subtriangular, with 5dorsal setae in addition to 2–3 marginal. Inferior volsella74–88, 81mm long, with dorsal microtrichia, and 14 setaeapically. Median volsella (Fig. 18) 56–66, 61 mm long, withsubulate setae fused into a plate with apical points. HR1.02–1.05, 1.03; HV 2.57–2.72 (2).

Pupa (n = 1–2). Total length 3.39mm. Exuviae slightly dark.

Cephalothorax. Frontal apotome (Fig. 23) slightly rugu-lose anteriorly. Frontal setae 42mm long. Antepronotals notobservable. Precorneals taeniate, close together; anterior pre-corneals 40–50 mm long; median precorneals 76–80mm long;posterior precorneals 100–116mm long. Anterior dorsocen-trals Dc1 20–24mm long, Dc2 26–44mm long, Dc3 12–18mmlong, Dc4 42mm long. Dc1 2–4mm in front of Dc2, Dc1

88–100mm in front of Dc3 and Dc3 2mm in front of Dc4. Thoracic horn (Fig. 24) 356mm long, 20mm wide, with finespinules on apical 1/3 of its length. Nose of wing sheath14–16mm long.

Abdomen. Tergite I bare; spines on tergites II–VI arrangedin paired circular patches. Tergite II (Fig. 25) with transverseposterior patch of very distinct spinules. Median shagreenessentially absent, weak and sparse shagreen present cau-dolaterally on tergites IV and V. Number of spines on T II–VIas 60–80, 60–70, 45–50, 30–45, 15–25. Caudal hookletsoccupying approximately median 1/2 of tergite II, about70–90 hooklets. Caudal spur 14–20mm long. L-setae on seg-ments II–VIII as 2, 2, 3, 3, 4, 4, 5; those on segments II andIII all narrowly taeniate; IV with 1 narrowly taeniate and 2broadly taeniate; V–VIII with all broadly taeniate. Lengths(in mm) of L3 and L4 on segment VIII 120 and 160. Anal lobe(Fig. 26) with hair-like seta; 21–26 taeniae in fringe; longesttaeniae 300–380 mm long. Male genital sac overreaches anallobe by 112–120mm.

Fourth instar larva (n = 1). Total length 3.12mm. Headcapsule length 0.28mm.

Head. Antenna as in Figure 27. Length of antennal seg-ments (in mm): 100, 22, 8, 6, 2. AR 2.63. Basal antennalsegment 20mm wide, distance from base to ring organ 4mm,to basal mark of seta 60mm. Blade 29mm long, accessoryblade 14mm long. Apical style of second segment 7 mm long, Lauterborn organ 6mm long, pedicel 6 mm long. Pecten epipharyngis a simple broad comb without indica-tion of division into parts. Posterior chaetulae laterales with conspicuously long branches. Premandible 60 mm long.Mandible (Fig. 28) 116mm long. Mentum (Fig. 29) 80 mmwide, with median tooth 14 mm wide with lateral notcheswhich may be more or less worn down; ventromental platewidth/length 2.92, number of ventromental plate striationsabout 30. Postmentum 120 mm long.

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Abdomen. Anterior parapods as in Figure 30. Procercus (Fig. 31) 20mm long, 12mm wide, anal setae 520 mm long.Supraanal seta 120 mm long; length of supraanal setae/lengthof anal setae 0.23. Posterior parapods and anal tubuli notmeasurable.

Third instar larvae (n = 1). Total length 2.76mm. Headcapsule length 0.20mm.

Head. Length of antennal segments (in mm): 90, 18, 8, 6,4. AR 2.5. Basal antennal segment 16mm wide, distance frombase to ring organ 2mm, to basal mark of seta 56mm.

Blade 33mm long, accessory blade 17 mm long. Apical style of second segment 10 mm, Lauterborn organ 9mm long,pedicel 7mm long. Premandible 58 mm long. Mandible 100mm long. Mentum 72mm wide, with median teeth 12mm wide; ventromental plate width/length 3.50, numberof ventromental plate striations about 30. Postmentum96–100mm long.

Abdomen. Procercus 20 mm long, 14mm wide; anal setae440mm long. Supraanal seta 104mm long, length ofsupraanal setae/length of anal setae 0.24. Posterior parapods160mm long. Anal tubuli not measurable.

Figs. 15–22. Rheotanytarsus exiguus (Johannsen) (Figs. 15–18) and R. meridionalis (Johannsen) (Figs. 19–22), male imagines: (15, 19) analpoint and dorsal aspect of left gonocoxite and gonostylus; (16, 20) hypopygium with anal point and tergite IX removed, left dorsal aspect,right ventral aspect; (17, 21) superior volsella; (18, 22) median volsella.

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Figs. 23–31. R. exiguus (Johannsen), pupa (Figs. 23–26) and larva (Figs. 27–31): (23) frontal apotome; (24) thoracic horn; (25) tergitesII–IV; (26) tergite VIII and anal lobe; (27) antenna; (28) mandible; (29) mentum; (30) anterior parapod; (31) procercus.

Second instar larvae (n = 1). Total length 1.85 mm. Headcapsule length 0.18 mm.

Head. Length of antennal segments (in mm): 100, 20, 8,4, 2. AR 2.94. Basal antennal segment 18 mm wide, distance

from base to ring organ 4mm, to basal mark of seta 52 mm.Blade 17mm long, accessory blade 10 mm long. Apical styleof second segment. Lauterborn organ and pedicel not observ-able. Premandible not observable. Mandible 100 mm long.

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Mentum 76 mm wide, with median teeth 12 mm wide; ventromental plate width/length 3.25, number of ventromental plate striations not countable; postmentum 110mm long.

Abdomen. Procercus 14 mm long, 16mm wide; anal setae420mm long. Supraanal seta 60 mm long, length of supraanalsetae/length of anal setae 0.14. Posterior parapods and analtubuli not measurable.


The adults of R. exiguus (Johannsen) can be separated fromall other Neotropical species by lacking spurs on mid andhind tibia.

Distribution

The species was described from New Mexico in the USA(Johannsen, 1905). Later Curry & Curry (1971) recorded thespecies from St. Croix in the Caribbean, based on larvae andlarval cases only. We have not examined the larvae from St.Croix, and regard the record as tentative as earlier records ofRheotanytarsus from North America often were referred toR. exiguus.

The acerbus group

The group comprises 5 species from the Oriental, Neotropi-cal and eastern part of the Palaearctic zoogeographicalregions. The known pupae have a thoracic horn which is bareor with points at most in apical 1/3–1/4, paired, circular ante-rior spine patches on tergites II–V, posterior spinule patch ontergite II divided, caudal hooklets on tergite II occupying lessthan median 1/3, and anal lobe with hair-like dorsal seta.

In the males the anal point is spatulate or narrow with V-shaped open crest, the superior volsella is rounded, themedian volsella at most reaches beyond the apex of the supe-rior volsella, and the gonostylus is abruptly tapered.

Rheotanytarsus hamatus Sublette et Sasa

Rheotanytarsus hamatus Sublette and Sasa, 1994: 52.Rheotanytarsus hamatus Sublette et Sasa; Spies and Reiss, 1996:

73.Rheotanytarsus hamatus Sublette et Sasa; Sublette et al., 1998: 137.The species is described in detail by Sublette and Sasa (1994).

Distribution

The species was described from Guatemala. Recently it hasbeen recorded from the Grand Canyon in Arizona, USA(Sublette et al., 1998).

Rheotanytarsus meridionalis (Johannsen) (Figs. 19–22)

Tanytarsus (Rheotanytarsus) meridionalis Johannsen, 1938: 222

Rheotanytarsus meridionalis (Johannsen); Spies & Reiss, 1996: 73

Material examined

Holotype �: Puerto Rico, Yúnez River, 14.VIII.1935, J.Garzia-Diaz (on slide) (CUC); 15 ��, 1 � head, 7 ��paratypes (on 3 slides) as holotype, 1 � as holotype except19.VI.1935 (CUC).

Redescription

Male imago (n = 1). Total length 1.88mm. Wing length 1.04mm. Total length/wing length 1.81. Wing length/length ofprofemur 1.58. Thorax slightly dark, abdomen and legs pale.

Head. AR 0.42. Thirteenth flagellomere 212mm long.Length of palpomeres (in mm): 24, 26, 76, 84, 168. Fifthpalpomere/third palpomere 2.21.

Thorax. Dorsocentrals 9, acrostichals 20. Scutellum with6 setae.

Wing. VR 1.52. Brachiolum with 1 seta, R with 20, R1

with 23, R4+5 with 51 setae. Sc and M bare. RM with 2 setae,M1+2 with 58, M3+4 with 25, Cu with 12, Cu1 with 16, PCuwith 44 and An with 26 setae. Cells m with 20 setae, r4+5 withabout 300, m1+2 with about 250, m3+4 with 150, cu and aneach with 60 setae.

Legs (Table 4). Spur of front tibia 16 mm long, spurs ofmiddle tibia 10 and 18 mm long; of hind tibia 18 and 22 mmlong, all excluding comb. Comb of middle tibia 10mm long,of hind tibia 12mm long. Width at apex of front tibia 38 mm,of middle tibia 32mm, of hind tibia 36 mm.

Hypopygium (Figs. 19, 20). Anal tergite with open, V-shaped tergite bands. Tergite IX with 9 setae. Anal point 52mm long, 22mm wide at base, 6mm at apex. Crest welldeveloped and V-shaped. Laterosternite IX with 1 setae.Phallapodeme 68mm long, transverse sternapodeme 44 mmlong. Gonocoxite 100mm long, gonostylus 94 mm long.

Table 3. Lengths (in mm) and proportions of legs of Rheotanytarsus exiguus (Johannsen).


p1 700 408–440 644–692 352–376 284–292 208–212 100–104 1.57–1.58 1.88 1.65 –p2 660 508–520 248–272 140–160 108–120 72–80 60 0.49–0.52 3.46 4.34 –p3 740 652–700 420 260 228 144 80 0.59 2.77 3.57 –

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Superior volsella (Fig. 21) 34mm long, oval, with 5 dorsalsetae in addition to 2 marginal. Inferior volsella 76 mm long,with dorsal microtrichia and 12 setae apically. Medianvolsella (Fig. 22) 52mm long, with lamelliform setae fusedinto plate with apical points. HR 1.06, HV 2.00.


R. meridionalis (Johannsen) is similar to R. hamatus Subletteet Sasa, but can be separated on having a median volsellawith apical plate.

Distribution

The species is known from Puerto Rico only.

The pellucidus group

The group is revised by Kyerematen et al. (2000). There isone known species from Mexico:

Rheotanytarsus contrerasi Andersen et Sæther

Rheotanytarsus contrerasi Andersen et Sæther in Kyerematen,Sæther and Andersen, 2000: 166.

The species is described in detail in Kyerematen et al. (2000).The species is similar to R. pellucidus (Walker, 1848) (syn.: R. dis-

tinctissimus (Brundin, 1947)), and as pointed out by Kyerematenet al. (2000) could be regarded as a subspecies or even a smallecotype of this species.

Distribution

The species is known from Mexico only.

The calakmulensis group

The male of this monotypic group is characterised by havingsetae on veins M and RM, anal tergite bands V-shaped andmedially joined, spatulate anal point with V-shaped opencrest, rounded superior volsella, median volsella extendingbeyond superior volsella, and gonostylus abruptly taperedwith parallel-sided apical portion.

Rheotanytarsus calakmulensis sp. n. (Figs. 32–38)

Type material

Holotype �: Mexico, Campeche, Calakmul BiosphereReserve, Ejdo. Nvo. Becan, El Chorro, 18°35¢25.5≤N,89°15¢28.8≤W, 130 m a.s.l., Malaise trap, 30.IV.1997, A.Contreras-Ramos et al. (IEXA). Paratypes: 20 �� as holo-type (3 �� IEXA, 17 �� ZMBN).

Etymology

Named after the Calakmul Biosphere Reserve in Campeche,Yucatán Peninsula, Mexico, using the Latin suffix -ensisdenoting place, locality.

Description

Male imago (n = 10, except when otherwise stated). Totallength 1.99–2.08, 2.03mm. Wing length 1.12–1.26, 1.18mm. Total length/wing length 1.61–1.78, 1.71. Wing length/length of profemur 1.67–1.75, 1.70.Thorax and abdomen pale, legs pale with apical 1/4 of femurdark.

Head (Fig. 32). AR 0.67–0.72, 0.69. Thirteenth flagel-lomere 332–380, 352 mm long. Temporal setae 7–8, 7; includ-ing 3 inner verticals; 2–3, 2 outer verticals, and 2postorbitals. Clypeus with 14–19, 15 setae. Tentorium 64–86,78mm long; 16–20, 17 mm wide at sieve pore; 6–10, 9 mmwide at posterior tentorial pit. Stipes 90–110, 98mm long;18–26, 21mm wide. Length of palpomeres (in mm): 26–30,27; 28–30, 29; 82–96, 87; 80–84, 82; 158–176, 164. Fifthpalpomere/third palpomere 1.67–2.05.

Thorax (Fig. 33). Dorsocentrals 9–12, 10; acrostichals18–22, 20. Scutellum with 2–3, 3 setae.

Wing (Fig. 34). VR 1.50–1.55, 1.52. Brachiolum with 1seta; R with 17–23, 20; R1 with 25–29, 27; R4+5 with 59–64,61 setae. Sc and M bare. RM with 1–2, 2 setae; M1+2 with58–70, 62; M3+4 with 27–29, 28; Cu with 15–17, 16; Cu1 with16–18, 17; PCu with 47–57, 52; and An with 28–31, 29 setae.Cells m with 10 setae, r4+5 with about 400, m1+2 with about250, m3+4 with about 150, cu with about 65 and an with about55 setae.

Legs (Table 5). Spur of front tibia 12–14, 13mm long;spurs of middle tibia 10–12, 10 and 16–18, 17mm long; of

Table 4. Lengths (in mm) and proportions of legs of Rheotanytarsus meridionalis (Johannsen).


p1 660 300 784 420 316 208 100 2.61 1.67 1.22 –p2 608 420 248 132 84 64 48 0.59 3.89 4.14 –p3 640 520 384 216 184 116 64 0.74 2.66 3.02 –

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Figs. 32–38. Rheotanytarsus calakmulensis sp. n., male imago: (32) head; (33) thorax; (34) wing; (35) anal point and dorsal aspect of leftgonocoxite and gonostylus; (36) hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect; (37) superiorvolsella; (38) median volsella.

hind tibia 16–18, 16 and 16–18, 17mm long, all excludingcomb. Comb of middle tibia 10–14, 13 mm long; of hind tibia 14–16, 14 mm long. Width at apex of front tibia 38–40,38mm; of middle tibia 34–36, 35 mm; of hind tibia 38–42, 40mm.

Hypopygium (Figs. 35, 36). Anal tergite with medially fused, V-shaped bands. Tergite IX with 7–10, 9 setae. Anal point 50–60, 55 mm long; 14–20, 16mm wide at base;

4–8, 6mm wide at apex. Crest well developed and V-shapedwith 2–3, 2 setae between anal tergite bands. LaterosterniteIX with 1 setae. Phallapodeme 64–68, 67mm long; transversesternapodeme 20–24, 23 mm long. Gonocoxite 86–92, 88mm long; gonostylus 90–96, 92 mm long. Superior volsella(Fig. 37) 28–32, 31mm long, oval, with 4 dorsal setae in addi-tion to 2 marginal. Inferior volsella 64–68, 65 mm long, withmicrotrichia dorsally, and 13–17, 15 strong, apical setae.

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Median volsella (Fig. 38) 40–56, 51 mm long, with lamelli-form setae fused into plates with few apical points. HR0.93–0.98, 0.95; HV 2.12–2.26, 2.19.


R. calakmulensis sp. n. groups with R. foliatus sp. n. and R.baculus sp. n. in having a median volsella extending wellbeyond apex of superior volsella, but not reaching apex ofinferior volsella. It can be separated from both in having anAR of about 0.7, while R. foliatus has an AR of about 0.3and R. baculus an AR of about 0.15.


The species is known from the Calakmul Biosphere Reserve in Mexico only. The specimens were taken in alowland rainforest area, with ponds and lakes and seasonalstreams.

The trivittatus group

The group comprises 11 species from the Afrotropical, Aus-tralian, Oriental, Neotropical and Palaearctic zoogeographi-cal regions. The pupae have a thoracic horn without medianbend, tergites II–V or II–VI with paired anterior circularspine patches, tergite II with posterior shagreen patchdivided, except for one species with segment VIII with cau-dolateral comb of 3–6 curved, thorn-like spurs, and anal lobewith taeniate or hair-like dorsal seta.

The male imagines have posterior margin of tergite IXstraight or with shoulders or projections to each side of theanal point, median volsella reaching at least apex of inferiorvolsella, with setae fused into apical plate(s), and gonostylususually not abruptly tapered.

Rheotanytarsus foliatus sp. n. (Figs. 39–45)

Type material

Holotype �: Costa Rica, Heredia Province, La Selva Biological Station, 10°26¢N 83°59¢W, 150m a.s.l., Malaisetrap, 3.IV.1993, O. A. Sæther (ZMBN Type No. 337).

Paratypes: 2 �� as holotype; 2 �� as holotype except2.III.1993. 2 �� Mexico, Nuevo León, Allende, Rio Ramosat Raices, 25°14¢53≤N 100°02¢07≤W, 20.IX.1998, light trap,T. Andersen & A. Contreras-Ramos (1 � IEXA, 1 �ZMBN).

Etymology

From the Latin foliatus meaning leaf, referring to the leaf-shaped plate of the median volsella.

Description

Male imago (n = 7, except when otherwise stated). Totallength 1.53–2.00, 1.67mm. Wing length 0.94–1.14, 1.04mm.Total length/wing length 1.49–1.75, 1.61. Wing length/lengthof profemur 1.85–2.11, 1.95. Thorax and legs slightly dark,abdomen pale.

Head (Fig. 39). AR 0.23–0.35, 0.30 (6). Thirteenth fla-gellomere 118–168, 145 (6) mm long. Temporal setae 7–8, 8including 3 inner verticals, 2–3, 3 outer verticals, and 2 pos-torbitals. Clypeus with 13–17, 15 setae. Tentorium 52–60, 57mm long; 12–14, 13mm wide at sieve pore; 6–8, 6mm wideat posterior tentorial pit. Stipes 60–90, 73mm long; 14–28,20mm wide. Length of palpomeres (in mm): 18–24, 22;20–26, 23; 54–66, 58; 58–78, 67 (6); 110–136, 119 (6). Fifthpalpomere/third palpomere 1.67–2.27, 2.04 (4).


Wing (Fig. 41). VR 1.50–1.64, 1.54. Brachiolum with 1seta; R with 10–16, 12; R1 with 14–19, 16; R4+5 with 31–44,39 setae. Sc and M bare. RM with 0–2, 0 setae; M1+2 with30–48, 37; M3+4 with 15–25, 20; Cu with 9–14, 11; Cu1 with11–13, 12; PCu with 28–37, 34; and An with 15–21, 18 setae.Cells m with 2 setae, r4+5 with about 150, m1+2 with about110, m3+4 with 35, cu with 10, and an with 10 setae.

Legs (Table 6). Spur of front tibia 10–16, 13mm long;spurs of middle tibia 4–10, 9 and 12–16, 14mm long; of hindtibia 10–18, 15 (6) and 12–20, 16 (6) mm long; all excludingcomb. Comb of middle tibia 10–12, 11 mm long; of hind tibia12–14, 13 (6) mm long. Width at apex of front tibia 30–36,32mm; of middle tibia 28–30, 30mm; of hind tibia 30–34, 32(6) mm.

Table 5. Lengths (in mm) and proportions of legs of Rheotanytarsus calakmulensis sp. n.


p1 664–720 280–328 872 (2) 432–440 320 (2) 240–248 96 (2) 2.66–2.72 1.73–1.76 1.19–1.20 –698 308 (2) (2) (2) (2) (2)

p2 592–648 424–464 256–272 120–144 88–96 56–64 40 (3) 0.59–0.64 4.00–4.24 3.73–4.06 5.8–6.4618 447 (3) (3) (3) (3) (3) (3) (3) (3)

p3 640–704 528–584 360–392 208–232 168–192 96–128 48–64 0.65–0.68 2.70–2.84 3.24–3.34 5.3–8.0666 556 372 222 182 114 58 0.67 2.77 3.28 (3)

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Figs. 39–45. Rheotanytarsus foliatus sp. n., male imago: (39) head; (40) thorax; (41) wing; (42) anal point and dorsal aspect of left gono-coxite and gonostylus; (43) hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect; (44) superior volsella;(45) median volsella.

Hypopygium (Figs. 42, 43). Anal tergite with weak, open basal tergite band, and open, V-shaped bands. TergiteIX with 7–9, 8 setae. Anal point 46–58, 51 mm long; 12–14,14mm wide at base; 4–8, 6mm wide at apex. Crest well devel-oped and V-shaped with 2–3, 2 setae in between anal tergitebands. Laterosternite IX with 1 setae. Phallapodeme 50–70,

55mm long; transverse sternapodeme 22–30, 26 mm long.Gonocoxite 64–82, 76mm long; gonostylus 56–76, 74mmlong. Superior volsella (Fig. 44) 26–38, 31 mm long, subtriangular, with knob-like apical projection, with fewmicrotrichia, and 2–4, 3 setae in addition to 2 marginal. Infe-rior volsella 52–62, 58 mm long, with microtrichia, and

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11–13, 12 apical setae. Median volsella (Fig. 45) 34–48, 39mm long, with lamelliform setae fused into a leaf-likeplates with few apical points. HR 1.06–1.19, 1.11; HV2.10–2.79, 2.45.


R. foliatus sp. n. groups with R. calakmulensis sp. n. and R.baculus sp. n. in having a median volsella extending wellbeyond apex of superior volsella, but not reaching apex ofinferior volsella. It can be separated from both in having asubtriangular superior volsella with apex produced giving aknob-like appearance, in addition to a gonostylus with long,completely parallel-sided apical portion.


The species is known from Costa Rica and Mexico. The spec-imens from Costa Rica were taken in a lowland rainforestarea close to a rather slow flowing river, while the specimensfrom Mexico were taken at a rather fast flowing lowland riverwith stony and sandy substratum.

Rheotanytarsus kusii sp. n. (Figs. 46–52)

Type material

Holotype �: Mexico, Nuevo León, Allende, Rio Ramos at Raices, 25°14¢53≤N 100°02¢07≤W, light trap, 20.IX.1998,T. Andersen & A. Contreras-Ramos (ZMBN Type No. 338).

Etymology

Named after the senior author’s brother, Kusi Kyerematen.

Description

Male imago (n = 1). Total length 1.82mm. Wing length 1.15mm. Total length/wing length 1.58. Wing length/length ofprofemur 1.89. Body entirely pale.

Head (Fig. 46). AR 0.46. Thirteenth flagellomere 228 mmlong. Temporal setae 6, including 3 inner verticals, 2 outerverticals, and 1 postorbitals. Clypeus with 13 setae. Tento-

rium 64 mm long, 16mm wide at sieve pore and 8 mm wide atposterior tentorial pit. Stipes 98mm long, 28mm wide.Length of palpomeres 1–4 (in mm): 24, 26, 72, 84.

Thorax (Fig. 47). Dorsocentrals 7, acrostichals 14. Scutel-lum with 3 setae.

Wing (Fig. 48). VR 1.59. Brachiolum with 1 seta, R with17, R1 with 21, R4+5 with 48 setae. Sc and M bare. RM with1 seta, M1+2 with 49, M3+4 with 29, Cu with 14, Cu1 with 14,PCu with 43, and An with 22 setae. Cells m with 5 setae, r4+5

with about 150, m1+2 with about 150, m3+4 with 55, cu with20, and an with 13 setae.

Legs (Table 7). Spur of front tibia 20mm long, spurs ofmiddle tibia 6 and 14 mm long, of hind tibia 14 and 16 mmlong, all excluding comb. Comb of middle tibia 10 mm long,of hind tibia 14mm long. Width at apex of front tibia 34 mm,of middle tibia 30mm, of hind tibia 34 mm.

Hypopygium (Figs. 49, 50). Anal tergite with widely openbasal tergite band and open V-shaped bands. Tergite with 8setae. Anal point 62 mm long, 22mm wide at base, 8 mm wideat apex. Crest well developed, open and V-shaped with 2 setae in between anal tergite bands. Laterosternite IX with 1setae. Phallapodeme 62 mm long, transverse sternapodeme 20mm long. Gonocoxite 74 mm long, gonostylus 72 mm long.Superior volsella (Fig. 51) 24 mm long, subquadrangular,with posterior margin produced, with microtrichia, and with4 dorsal setae in addition to 2 marginal. Inferior volsella 58mm long, with dorsal microtrichia, and 15 strong, apicalsetae. Median volsella (Fig. 52) 34 mm long, with lamelli-form setae fused into plates with apical points. HR 1.03, HV2.52.


R. kusii sp. n. is rather distinct among the Neotropical speciesin having a subquadrangular superior volsella. It groups withR. exiguus (Johannsen) on the parallel-sided anal point, butcan be easily separated from this species on the presence ofspurs on mid and hind tibiae.


The species is known from Mexico only. The specimen wastaken at a rather fast flowing lowland river with stony andsandy substratum.

Table 6. Lengths (in mm) and proportions of legs of Rheotanytarsus foliatus sp. n.


p1 488–576 188–256 – – – – – – – – –531 225

p2 464–544 328–408 180–216 88–104 64–72 40–64 32–40 0.50–0.55 4.15–4.93 4.40–4.52 5.0–6.0504 385 198 (5) 94 (5) 69 (5) 48 (5) 34 (5) 0.52 (5) 4.45 (5) 4.45 (5) (3)

p3 512–600 416–488 240–280 152–176 152–160 88–104 48–56 0.55–0.59 2.70–2.91 3.78–3.94 5.4553 (6) 453 (6) 261 (4) 165 (4) 151 (4) 96 (4) 0 (4) 0.57 (4) 2.78 (4) 3.90 (4) (1)

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Figs. 46–52. Rheotanytarsus kusii sp. n., male imago: (46) head; (47) thorax; (48) wing; (49) anal point and dorsal aspect of left gonocox-ite and gonostylus; (50) hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect; (51) superior volsella;(52) median volsella.

Rheotanytarsus nuamae sp. n. (Figs. 53–59)

Type material

Holotype �: Mexico, Nuevo León, Allende, Rio Ramos atRaices, 25°14¢53≤N 100°02¢07≤W, light trap, 20.IX.1998, T.Andersen & A. Contreras-Ramos (ZMBN Type No. 339).

Etymology

Named after the senior author’s sister, Nuama Kyerematen.

Description

Male imago (n = 1). Total length 2.04 mm. Wing length

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1.22mm. Total length/wing length 1.67. Wing length/lengthof profemur 1.75. Body entirely pale.

Head (Fig. 53). AR 0.51. Thirteenth flagellomere 256 mmlong. Temporal setae 7, including 3 inner verticals, 2 outerverticals, and 2 postorbitals. Clypeus with 14 setae. Tento-rium 90 mm long, 16mm wide at sieve pore and 10 mm wideat posterior tentorial pit. Stipes 100 mm long, 30mm wide.Length of palpomeres (in mm): 30, 34, 82, 94, 140. Fifthpalpomere/third palpomere 1.71.

Thorax (Fig. 54). Dorsocentrals 9, acrostichals 16. Scutel-lum with 5 setae.

Wing (Fig. 55). VR 1.55. Brachiolum with 1 seta, R with17, R1 with 24, R4+5 with 52 setae. Sc and M bare. RM with2 seta, M1+2 with 69, M3+4 with 30, Cu with 16, Cu1 with 17,PCu with 65, and An with 26 setae. Cells m with 10 setae,r4+5 with about 300, m1+2 with about 200, m3+4 with 120, cuwith 40, and an with 60 setae.

Legs (Table 8). Spur of front tibia 16 mm long, spurs ofmiddle tibia 10 and 14 mm long, of hind tibia 16 and 18 mmlong, all excluding comb. Comb of middle tibia 14mm long,of hind tibia 14 mm long. Width at apex of front tibia 40 mm,of middle tibia 36 mm, of hind tibia 40 mm.

Hypopygium (Figs. 56, 57). Anal tergite with open, V-shaped bands. Tergite IX with projections to each side of anal point and with 11 setae. Anal point 58mm long, 24 mm wideat base, 6mm wide at apex. Crest well developed, open and V-shaped with 3 setae in between anal tergite bands. Laterosternite IX with 1 setae. Phallapodeme 60mm long,transverse sternapodeme 26 mm long. Gonocoxite 90 mmlong, gonostylus 88 mm long. Superior volsella (Fig. 58) 28mm long, rounded, with 4 dorsal setae in addition to 2 marginal. Inferior volsella 66mm long, with dorsalmicrotrichia, and with 16 strong and 5 weaker apical setae.Median volsella (Fig. 59) 42mm long, basal with strong, lamelliform setae pointing caudad, and with apicallamelliform setae fused into plates with apical points. HR1.02, HV 2.32.


R. nuamae sp. n. can be separated from all the otherNeotropical species by the strong, lamelliform setae basal onmedian volsella. It is similar to R. scutulatus sp. n., but canbe distinguished by having a rounded superior volsella, whilethe superior volsella in R. scutulatus is subtriangular. Further,R. nuamae has an AR of about 0.50, while the AR of R. scu-tulatus is less than 0.25.


The species is known from Mexico only. The specimen wastaken at a rather fast flowing lowland river with stony andsandy substratum.

Rheotanytarsus scutulatus sp. n. (Figs. 60–66)

Type material

Holotype �: Costa Rica, Guanacaste Province, GuanacasteConservation Area, Cerro Cacao, Rio San Josecito, 1000ma.s.l., Malaise trap, 3–7.V.1993, T. Andersen (ZMBN TypeNo. 340). Paratypes: 9 �� same data as holotype (ZMBN).

Etymology

From the Latin scutula meaning diamond-shaped, referringto shape of the superior volsella.

Description

Male imago (n = 10, except when otherwise stated). Totallength 1.84–2.18, 1.95mm. Wing length 1.12–1.23, 1.16mm.Total length/wing length 1.62–1.90, 1.68. Wing length/lengthof profemur 1.79–1.96, 1.91. Thorax and abdomen pale, legspale with apical 1/4 of femur dark.

Head (Fig. 60). AR 0.21–0.24, 0.22. Thirteenth flagel-lomere 104–124, 112 mm long. Temporal setae 7–8, 7; includ-ing 3 inner verticals; 2–3, 2 outer verticals; and 2postorbitals. Clypeus with 14–22, 19 setae. Tentorium 54–76,68mm long; 12–14, 13mm wide at sieve pore; 6–8, 7mm wideat posterior tentorial pit. Stipes 86–92, 89mm long; 14–26, 20mm wide. Length of palpomeres (in mm): 24–32, 27; 24–32, 28; 52–72, 63 (8); 74–84, 79 (8); 146–150, 148 (8). Fifth palpomere/third palpomere 2.05–2.81, 2.37 (8).


Wing (Fig. 62). VR 1.50–1.59, 1.54. Brachiolum with 1seta; R with 15–23, 19; R1 with 24–35, 28; R4+5 with 50–63,56 setae. Sc and M bare. RM with 1–2, 2 setae; M1+2 with50–73, 62; M3+4 with 25–32, 29; Cu with 14–24, 18; Cu1 with13–17, 15; PCu with 50–70, 59; and An with 24–34, 30 setae.Cells m with 10 setae, r4+5 with about 300, m1+2 with about250, m3+4 with about 140, cu with about 70, and an with about100 setae.

Table 7. Lengths (in mm) and proportions of legs of Rheotanytarsus kusii sp. n.


p1 608 268 760 360 272 208 84 2.84 1.77 1.15 3.7p2 600 448 228 112 84 52 40 0.51 4.43 4.60 4.2p3 632 520 300 196 172 104 76 0.58 2.65 3.84 6.0

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Figs. 53–59. Rheotanytarsus nuamae sp. n., male imago: (53) head; (54) thorax; (55) wing; (56) anal point and dorsal aspect of left gono-coxite and gonostylus; (57) hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect; (58) superior volsella;(59) median volsella.

Table 8. Lengths (in mm) and proportions of legs of Rheotanytarsus nuamae sp. n.


p1 696 304 856 412 320 248 100 2.82 1.72 1.17 3.3p2 652 488 260 – – – – 0.53 – 4.38 5.0p3 688 580 320 212 196 120 64 0.55 2.68 3.96 4.25

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Figs. 60–66. Rheotanytarsus scutulatus sp. n., male imago: (60) head; (61) thorax; (62) wing; (63) anal point and dorsal aspect of left gono-coxite and gonostylus; (64) hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect; (65) superior volsella;(66) median volsella.

Legs (Table 9). Spur of front tibia 12–16, 14mm long;spurs of middle tibia 6–12, 9 and 12–16, 14 mm long; of hindtibia 14–16, 14 (9) and 16–20, 17 (9) mm long, all excludingcomb. Comb of middle tibia 10–12, 12 mm long; of hind tibia

14–16, 14mm long. Width at apex of front tibia 38–40, 39mm;of middle tibia 32–36, 34 mm; of hind tibia 38–40, 39 (9) mm.

Hypopygium (Figs. 63, 64). Anal tergite with open, V-shaped bands. Tergite IX with 7–9, 8 setae. Anal point 54–62,

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56mm long; 14–26, 19 mm wide at base; 4–6, 6mm wide at a pex. Crest well developed and V-shaped with 3–5, 3 setaein between anal tergite bands. Laterosternite IX with 1 setae. Phallapodeme 56–68, 63 mm long; transverse ster-napodeme 20–30, 25 mm long. Gonocoxite 72–90, 80 mmlong; gonostylus 66–78, 72mm long. Superior volsella (Fig.65) 24–34, 28mm long, subtriangular, with 4–5, 5 setae inaddition to 2 marginal. Inferior volsella 50–58, 54 mm long,with broad, subrectangular apex, with microtrichia dorsally,and with 13–16, 15 setae apically. Median volsella (Fig. 66)32–40, 35mm long, with lamelliform setae fused into broadplates with few apical points. HR 1.09–1.17, 1.12; HV2.39–3.03, 2.72.


R. scutulatus sp. n. is similar to R. nuamae sp. n., for diag-nostic characters see R. nuamae.



The thermae group

The group comprises 5 species distributed in the Afrotropi-cal, Oriental, Neotropical and in the eastern part of thePalaearctic zoogeographical regions. The only known pupahas a bare thoracic horn without median bend, tergites II–Vwith paired anterior circular spine patches, tergite II withposterior shagreen patch divided, and anal lobe with hair-likedorsal seta.

The male imagines have a median volsella reaching apexof inferior volsella, with setae fused into apical plate(s),usually with points, superior volsella is mostly rounded, andthe gonostylus is not abruptly tapered in most species.

Rheotanytarsus hanseni sp. n. (Figs. 67–73)

Type material

Holotype �: Mexico, Oaxaca, Candelaria Loxiela,8–11.I.1995, L. O. Hansen (ZMBN Type No. 341).

Paratypes: 3 �� as holotype (1 � IEXA, 2 �� ZMBN); 1 �, Morelos, 2.5 km W Huautla, Estacion Ceamish,18°27¢67≤N, 99°02¢48≤W, 940m a.s.l., 13.XI.1996, lighttrap, Zaragoza et al. (IEXA).

Etymology

Named after Lars Ove Hansen, who collected most of thematerial.

Description

Male imago (n = 5, except when otherwise stated). Totallength 2.25–2.74, 2.61mm. Wing length 1.34–1.43, 1.37mm.Total length/wing length 1.61–2.04, 1.91. Wing length/lengthof profemur 2.04–2.15, 2.10. Thorax light brown, abdomenpale, legs slightly dark in apical 1/4.

Head (Fig. 67). AR 0.46–0.51, 0.49. Thirteenth flagel-lomere 244–272, 254mm long. Temporal setae 7–10, 9;including 3–4, 4 inner verticals; 2–3, 3 outer verticals; and2–3, 3 postorbitals. Clypeus with 19–25, 21 setae. Tentorium88–110, 99mm long; 20–24, 22 mm wide at sieve pore; 12–14,12mm wide at posterior tentorial pit. Stipes 124–130, 128 mmlong; 26–36, 30mm wide. Length of palpomeres (in mm):30–32, 31; 36–42, 39; 94–112, 104; 94–104, 100; 176–182(2). Fifth palpomere/third palpomere 1.65–1.72 (2).


Wing (Fig. 69). VR 1.39–1.53, 1.48. Brachiolum with 1seta; R with 25–30, 27; R1 with 32–45, 36; R4+5 with 69–82,74 setae. Sc bare. M with 0–2, 0 seta; RM with 2; M1+2 with70–93, 83; M3+4 with 35–37, 36; Cu with 16–24, 19; Cu1 with20–21, 20; PCu with 69–92, 76; and An with 34–38, 36 setae.Cells m with 13 setae, r4+5 with about 350, m1+2 with about250, m3+4 with about 120, cu with about 80, and an with about90 setae.

Legs (Table 10). Spur of front tibia 18–22, 20 mm long;spurs of middle tibia 10–14, 12 and 14–18, 16mm long; ofhind tibia 14–16, 14 and 16–20, 18mm long; all excluding comb. Comb of middle tibia 14–16 14mm long; of hind tibia14–18, 17mm long. Width at apex of front tibia 42–44, 43mm; of middle tibia 40–42, 41 mm; of hind tibia 44–48, 47mm.

Table 9. Lengths (in mm) and proportions of legs of Rheotanytarsus scutulatus sp. n.


p1 576–640 256–312 696–808 328–360 240–296 192–216 88–100 2.51–2.90 1.74–1.87 1.14–1.23 –608 281 748 (9) 346 (9) 269 (9) 204 (9) 92 (9) 2.68 (9) 1.79 (9) 1.18 (9)

p2 544–600 400–472 216–248 104–152 72–80 48–56 32–40 0.49–0.57 4.10–4.79 4.26–4.67 3.7–5.6578 439 232 (9) 113 (9) 79 (9) 51 (9) 37 (9) 0.52 (9) 4.48 (9) 4.43 (9) (4)

p3 592–672 480–560 280–320 184–200 176–192 96–120 48–72 0.57–0.61 2.61–2.81 3.64–3.85 3.9–4.8624 514 306 (8) 190 (8) 182 (8) 105 (8) 57 (8) 0.59 (8) 2.72 (8) 3.75 (8) (4)

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Figs. 67–73. Rheotanytarsus hanseni sp. n., male imago: (67) head; (68) thorax; (69) wing; (70) anal point and dorsal aspect of left gono-coxite and gonostylus; (71) hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect; (72) superior volsella;(73), median volsella.

Hypopygium (Figs. 70, 71). Tergite IX with 8–11, 10setae. Anal point 60–66, 62 mm long; 20mm wide at base;8–10, 8mm wide at apex. Crest well developed, open and V-shaped with 4–7, 5 setae in between anal tergite bands. Lat-erosternite IX with 1 setae. Phallapodeme 74–84, 80 mmlong; transverse sternapodeme 18–26, 22 mm long. Gono-

coxite 94–114, 108mm long; gonostylus 92–108, 102mm long. Superior volsella (Fig. 72) 28–38, 34 mm long, rounded; inferior volsella 80–88, 83mm long; medianvolsella (Fig. 73) 76–86, 80 mm long, slightly sigmoid andreaching almost to the tip of the inferior volsella, with lamel-liform setae fused into rounded plates with apical points.

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Inferior volsella with microtrichia, superior and medianvolsellae without microtrichia. HR 1.02–1.12, 1.06; HV2.44–2.79, 2.58.


R. hanseni sp. n. can be separated from other Neotropicalspecies by having a second anal point crest close to the apexof the anal point. Except for R. contrerasi Andersen et Sætherit is the only species from this region with a median volsellareaching the apex of the inferior volsella. It differs from R.contrerasi by having the lamelliform setae of the medianvolsella fused into ovoid plates.


The species is known from Mexico only. The specimens weretaken close to rather fast flowing rivers.

The phaselus group

The group comprises 5 species from the Afrotropical, Ori-ental, and Neotropical zoogeographical regions. The onlyknown pupa has an anteriorly rugulose frontal apotome,frontal setae, thoracic horn with median bend, and spinulesin apical 2/3, tergites II–V with paired anterior circular spinepatches, tergite II with posterior shagreen patch divided,about 70 caudal hooklets occupying median half of tergite II,and anal lobe without dorsal seta.

The male imagines all have at least some setae betweenV-shaped anal tergite bands, superior volsella with posteriorextension, median volsella usually not reaching apex of supe-rior volsella, and the gonostylus usually is abruptly tapered,often with parallel-sided apical portion.

Rheotanytarsus guanacastensis sp. n. (Figs. 74–80)

Type material

Holotype �: Costa Rica, Guanacaste Province, GuanacasteConservation Area, Cerro Cacao, Rio San Josecito, 1000ma.s.l., Malaise trap, 3–7.V.1993, T. Andersen (ZMBN Type No. 342). Paratypes: 2 �� same data as holotype(ZMBN).

Etymology

Named after the Guanacaste Conservation Area, using theLatin -ensis denoting place, locality.

Description

Male imago (n = 1–3). Total length 1.84–2.14mm. Winglength 1.16–1.21mm. Total length/wing length 1.59–1.77.Wing length/length of profemur 1.88–1.93. Thorax, abdomenand legs pale.

Head (Fig. 74). AR 0.30–0.33. Thirteenth flagellomere148–172mm long. Temporal setae 8; including 3 inner verti-cals, 2–3 outer verticals, and 2–3 postorbitals. Clypeus with13–18 setae. Tentorium 74–82 mm long, 14–18mm wide atsieve pore and 10 mm wide at posterior tentorial pit. Stipes80–104mm long, 18–26mm wide. Length of palpomeres (in mm): 24–28, 26–32, 70–86, 78–82, 160–180. Fifthpalpomere/third palpomere 2.09–2.29.

Thorax (Fig. 75). Dorsocentrals 11–12, acrostichals18–20. Scutellum with 4–5 setae.

Wing (Fig. 76). VR 1.48–1.55. Brachiolum with 1 seta, Rwith 18–20, R1 with 20–29, R4+5 with 52–56 setae. Sc and Mbare. RM with 1–2 setae, M1+2 with 60–80, M3+4 with 23–27,Cu with 12–16, Cu1 with 13–14, PCu with 38–51, and Anwith 25–28 setae. Cells m with 10 setae, r4+5 with about 300,m1+2 with about 250, m3+4 with about 150, cu with 80, and anwith 100 setae.

Legs (Table 11). Spur of front tibia 16–18 mm long, spursof middle tibia 6–12 and 16–20 mm long, of hind tibia 16 and 18mm long, all excluding comb. Comb of middle tibia12–14mm long, of hind tibia 12–14 mm long. Width at apexof front tibia 38–40mm, of middle tibia 36–38mm, of hindtibia 40–42 mm.

Hypopygium (Figs. 77, 78). Anal tergite with open basaltergite band, and open V-shaped bands. Tergite IX with 7–8setae. Anal point 58–60 mm long, 16–20mm wide at base, 6–8mm at apex. Crest well developed and V-shaped with 3–4 setae in between anal tergite bands. Laterosternite IXwith 1 setae. Phallapodeme 62–70 mm long; transverse sternapodeme 22–24mm long. Gonocoxite 88–92 mm long,gonostylus 80–86 mm long. Superior volsella (Fig. 79) 32–38mm long, subtriangular with knob-like apical projection,with 3–4 dorsal setae in addition to 2 marginal. Inferior

Table 10. Lengths (in mm) and proportions of legs of Rheotanytarsus hanseni sp. n.


p1 628–680 360–416 748–800 400–428 296–332 212–248 100–112 1.91–2.10 1.68–1.72 1.29–1.41 –658 385 770 413 314 232 106 2.00 1.70 1.35

p2 600–684 504–544 284–320 156–180 120–136 82–88 52–64 0.56–0.59 3.33–3.38 3.81–3.89 –647 528 (3) (3) (3) (3) (3) (3) (3) (3)

p3 680–744 632–680 432–460 252–284 208–236 128–148 72–84 0.66–0.68 2.50–2.70 3.09–3.13 –719 659 (3) (3) (3) (3) (3) (3) (3) (3)

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Figs. 74–80. Rheotanytarsus guanacastensis sp. n., male imago: (74) head; (75) thorax; (76) wing; (77) anal point and dorsal aspect of leftgonocoxite and gonostylus; (78) hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect; (79) superiorvolsella; (80) median volsella.

Table 11. Lengths (in mm) and proportions of legs of Rheotanytarsus guanacastensis sp. n.


p1 600–644 276–300 752–812 372–376 280–292 220–224 92–96 2.54–2.72 1.74–1.80 1.19 –p2 612–660 464–500 260–276 124–128 92–100 60–64 48–52 0.55–0.57 4.00–4.22 4.00–4.20 4.6p3 648–708 556–600 392–400 216–224 192–208 120–124 60–64 0.67–0.70 2.69–2.79 3.11–3.27 –

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Figs. 81–86. Rheotanytarsus ramirezae sp. n., male imago: (81) head; (82) thorax; (83) anal point and dorsal aspect of left gonocoxite andgonostylus; (84) hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect; (85) superior volsella; (86) medianvolsella.

volsella 60–64 mm long, with dorsal microtrichia, and with14–16 setae apically. Median volsella (Fig. 80) 26–32 mmlong, with lamelliform setae fused into plates with apicalpoints. HR 1.07–1.10, HV 2.24–2.49.


R. guanacastensis sp. n. can be separated from other Neotropical species by the short, L-shaped medianvolsella.



Rheotanytarsus ramirezae sp. n. (Figs. 81–90)

Type material

Holotype � Mexico, Nuevo León, Santiago, 30km W Colade Caballo on road to Laguna de Sanchez, 19.IX.1998, drift

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Head (Fig. 81). AR 0.36. Thirteenth flagellomere 188 mmlong. Temporal setae 9, including 4 inner verticals, 3 outerverticals, and 2 postorbitals. Clypeus with 16 setae. Tento-rium 62 mm long, 24mm wide at sieve pore and 12 mm wideat posterior tentorial pit. Stipes 90 mm long, 24mm wide.Length of palpomeres 1–2 (in mm): 24, 28.

Thorax (Fig. 82). Dorsocentrals 10, acrostichals 18.Scutellum with 7 setae.

Wing. not measurable.Legs. Spur of front tibia broken, spurs of middle tibia 8

and 10mm long, of hind tibia 10 and 12 mm long, all exclud-ing comb. Comb of middle tibia 12mm long, of hind tibia 14mm long. Width at apex of front tibia 38 mm, of middle tibia 36mm, of hind tibia 38mm. Length of front femur 620mm,of middle femur 600 mm, of hind femur 680 mm; length of

Figs. 87–90. Rheotanytarsus ramirezae sp. n., pupa: (87), frontal apotome; (88) thoracic horn; (89) abdomen; (90) tergite II.

net, T. Andersen & A. Contreras-Ramos (ZMBN Type No.343).

Additional material

3 pupal exuviae as holotype.

Etymology

Named after Gladys Ramirez, who has made slide prepara-tions of chironomids for many years.

Description

Male imago (n = 1). Total length 2.88 mm. Thorax slightlybrown. Legs dark apically, abdomen pale.

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front tibia 360 mm, of mid tibia 460 mm, and of hind tibia 580mm; all tarsi lost.

Hypopygium (Figs. 83, 84). Anal tergite with open basaltergite band and open V-shaped bands. Tergite with 8 setae.Anal point 42 mm long, 30mm wide at base, 6mm wide at

apex. Crest well developed, open and V-shaped with 4 setaein between anal tergite bands. Laterosternite IX with 1 setae.Phallapodeme 84mm long, transverse sternapodeme 20 mmlong. Gonocoxite 106mm long, gonostylus 94 mm long.Superior volsella (Fig. 85) 30 mm long, subtriangular, large,

Figs. 91–97. Rheotanytarsus subtilis sp. n., male imago: (91) head; (92) thorax; (93) wing; (94) anal point and dorsal aspect of left gono-coxite and gonostylus; (95) hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect; (96) superior volsella;(97) median volsella.

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with 6 dorsal setae in addition to 2 marginal. Inferior volsella68mm long, with microtrichia, and 15 setae apically. Medianvolsella (Fig. 86) 44mm long, with lamelliform setae fusedinto plates with apical points. HR 1.13, HV 3.03.

Pupa (n = 2–3). Total length 3.39mm. Exuviae slightly dark.

Cephalothorax. Frontal apotome (Fig. 87) rugulose ante-riorly. Frontal setae 36–46mm long on tubercles. Medianantepronotals 130–152 mm long, lateral antepronotals 30–60mm long; both taeniate. Precorneals taeniate, closetogether; anterior precorneals 52–88 mm long; median pre-corneals 48–80 mm long; posterior precorneals 164–190 mmlong. Anterior dorsocentrals Dc1 10–20mm long, Dc2 40–60mm long, Dc3 38–70mm long, Dc4 10–14mm long. Dc1 2–4mm in front of Dc2, Dc1 96–118mm in front of Dc3 and Dc3

2–4mm in front of Dc4. Thoracic horn (Fig. 88) 360–380mmlong, 24–28mm wide, with median bend and fine spinules onapical 2/3 of its length. Nose of wing sheath 16–20mm long.

Abdomen (Fig. 89). Tergite I bare; spines on tergites II–Varranged in paired circular patches. Tergite II (Fig. 90) witha second pair of spine patches posteriorly. Median shagreenessentially absent, weak and sparse shagreen present cau-dolaterally on tergites V and VI. Number of spines on T II–Vas 90–150, 90–150, 60–90, 60–80. Caudal hooklets occupy-ing approximately median 1/2 of tergite II, about 70 hook-lets. Caudal spur 18–22mm long. L-setae on segmentsII–VIII as 3, 3, 3, 3, 4, 4, 4; those on segments II and III allhair-like; IV with 2 hair-like and 1 taeniate; V–VIII with alltaeniate. Lengths (in mm) of L3 and L4 on segment VIII140–144 and 90–100. Anal lobe bare; 17–20 taeniae infringe; longest taeniae 160–270 mm long. Male genital sacoverreaches anal lobe by 134 mm.


R. ramirezae sp. n. is similar to R. subtilis sp. n., but can beseparated on the shape of the gonostylus, which is not com-pletely parallel-sided apically, and on the median volsellawhich has a higher number of subulate setae.

The association between adult and pupa is tentative, basedonly on the fact that they were the only Rheotanytarsus col-

lected in the drift net samples at the small stream on the roadto Laguna de Sanchez.


The species is known from north-eastern Mexico only. Thespecimens were taken in a small, slow flowing mountainstream with silty bottom.

Rheotanytarsus subtilis sp. n. (Figs. 91–97)

Type material

Holotype �: Costa Rica, Guanacaste Province, GuanacasteConservation Area, Cerro Cacao, Rio San Josecito, 1000ma.s.l., Malaise trap, 3–7.V.1993, T. Andersen (ZMBN No.:344). Paratypes: 4 �� same data as holotype.

Etymology

From the Latin subtilis meaning thin, slender; referring to thethinning of the gonostylus in the distal half.

Description

Male imago (n = 5, except when otherwise stated). Totallength 2.11–2.94, 2.45mm. Wing length 1.21–1.35, 1.27mm.Total length/wing length 1.75–2.24, 1.93. Wing length/lengthof profemur 1.84–1.98, 1.93. Thorax and abdomen pale, legspale with apical 1/4 of femur dark.

Head (Fig. 91). AR 0.36–0.39, 0.37. Thirteenth flagel-lomere 180–196, 188 mm long. Temporal setae 8–9, 9; includ-ing 3–4, 4 inner verticals; 3 outer verticals; and 2postorbitals. Clypeus with 14–22, 19 setae. Tentorium 80–86,83mm long; 20–24, 22 mm wide at sieve pore; 10–14, 12 mmwide at posterior tentorial pit. Stipes 100–104, 101 mm long;18–24, 20mm wide. Length of palpomeres (in mm): 26–30,29; 26–30, 28; 86–110, 97; 92–110, 101; 180–194, 188. Fifthpalpomere/third palpomere 1.73–2.20, 1.95.


Wing (Fig. 93). VR 1.47–1.53, 1.51. Brachiolum with 1seta, R with 22–25, 23; R1 with 32–42, 36; R4+5 with 63–69,66 setae. Sc and M bare. RM with 2–3, 2 setae; M1+2 with

Table 12. Lengths (in mm) and proportions of legs of Rheotanytarsus subtilis sp. n.


p1 656–696 320–352 816–880 400–440 288–328 232–256 104–112 2.37–2.54 1.61–1.77 1.19–1.22 –667 339 (3) (3) (3) (3) (3) (3) (3) (3)

p2 632–680 472–520 280–312 136–160 104–112 64–72 40–56 0.58–0.62 3.75–3.98 3.72–4.00 –650 491 296 (4) 148 (4) 108 (4) 66 (4) 48 (4) 0.59 (4) 3.91 (4) 3.89 (4)

p3 656–720 592–640 440–464 248–264 200–224 80–136 64–72 0.70–0.74 2.66–2.78 2.68–2.96 –691 613 448 253 214 115 67 0.72 2.76 2.86

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72–80, 75; M3+4 with 30–35, 33; Cu with 19–25, 21; Cu1 with17–21, 19; PCu with 62–78, 70; and An with 30–36, 32 setae.Cells m with 16 setae, r4+5 with about 350, m1+2 with about300, m3+4 with about 200, cu with about 100, and an withabout 110 setae.

Legs (Table 12). Spur of front tibia 12–18, 14 mm long;spurs of middle tibia 8–12, 10 and 16–20, 19mm long; ofhind tibia 14–18, 16 and 16–20, 18mm long; all excludingcomb. Comb of middle tibia 14–16, 14 mm long; of hind tibia16–18, 18mm long. Width at apex of front tibia 40 mm; ofmiddle tibia 36–38, 37mm; of hind tibia 40–44, 42mm.

Hypopygium (Figs. 94, 95). Anal tergite with basal tergiteband and open V-shaped bands. Tergite IX with 5–10, 7 setae.Anal point 56–58, 57 mm long; 20–22, 20mm wide at base;4–8, 6mm wide at apex. Crest well developed and V-shapedwith 3–7, 4 setae between anal tergites bands. LaterosterniteIX with 1 setae. Phallapodeme 62–84, 71mm long; transversesternapodeme 20–28, 24mm long. Gonocoxite 86–100, 94mm long; gonostylus 82–100, 91mm long. Superior volsella(Fig. 96) 32–40, 36mm long, subtriangular, with 2–4, 3dorsal setae in addition to 2 marginal. Inferior volsella66–70, 69 mm long, with microtrichia, and 11–13, 12 setaeapically. Median volsella (Fig. 97) 46–54, 50 mm long, dis-tinctly curved with lamelliform setae fused into broad platewith many apical points. HR 1.00–1.05, 1.03; HV 2.48–3.13,2.68.


R. subtilis sp. n. is similar to R. ramirezae sp. n., for diag-nostic characters see R. ramirezae.



Acknowledgements

We are indebted to E. Richard Hoebeke, Collection Managerat Cornell University Insect Collection, New York, USA forlending us the type material of R. meridionalis (Johannsen).James E. Sublette, Tucson, Arizona kindly lent us specimensof R. exiguus (Johannsen). We are also indebted to AtilanoContreras-Ramos, Instituto de Biologia, UniversidadNacional Autónomia de Mexico (U.N.A.M.), Mexico, forlending us material of R. calakmulensis sp. n., to Lars Ove Hansen, Museum of Zoology, University of Oslo, for the material of R. hanseni sp. n. and to Karl Thunes, Museumof Zoology, University of Bergen, for the material of R. thunesi sp. n. Ole A. Sæther proof read the manuscript andgave many valuable suggestions, Gladys Ramirez made the slide preparations, and Karoline R. Klausen inked someof the drawings. The article was written while the seniorauthor had a scholarship from The Norwegian Universities’

Committee for Development, Research and Education(NUFU).

References

Bause E (1913): Die Metamorphose der Gattung Tanytarsus undeiniger verwandter Tendipedidenarten. Arch HydrobiolSuppl 2: 1–126.

Cranston PS (1997): Revision of Australian RheotanytarsusThienemann & Bause (Diptera: Chironomidae), withemphasis on immature stages. Invert tax 11: 705–734.

Cranston PS, Dillon ME, Pinder LCV, Reiss F (1989): 10. Theadult males of Chironominae (Diptera: Chironomidae) ofthe Holarctic region – Keys and diagnoses. In: WiederholmT, ed., Chironomidae of the Holarctic region. Keys anddiagnoses. Part 3. Adult males. Ent scand Suppl 34:353–502.

Curry LL, Curry MC (1971): The Chironomidae (Diptera)found in the U. S. Virgin Islands and Anegada, BritishVirgin Islands. Can Entomol 103: 310–314.

Dejoux C (1973): Contribution à l’étude premiers états des Chi-ronomides du Tchad. Description de Tanytarsus (Rheotany-tarsus) ceratophylli n. sp. (6e note). Cah O R S T O M, SérHydrobiol 7: 65–75.

Fittkau EJ (1960): Rheotanytarsus nigricauda n. sp. Chirono-midenstudien VI. Abh naturw Ver Bremen 35: 397–407.

Goetghebuer M (1954): Die Imagines (part). In: GoetghebuerM, Lenz F, eds., Tendipedidae (Chironomidae). b) Sub-familie Tendipedinae (Chironominae) (part). Fliegen palReg 3(1)(13c): 129–168.

Johannsen OA (1905): Aquatic nematocerous Diptera II. In:Needham JG, Morton KJ, Johannsen OA, eds., May fliesand midges of New York. Third report on aquatic insects.NY State Univ Mus Bul 86: 76–315.

Johannsen OA (1938): New species of Nematocera from PuertoRico. J Agric Univ Puerto Rico 22: 219–225.

Kieffer JJ (1909): Diagnoses de nouveaux Chironomidesd’Allemagne. Bull Soc Hist nat Metz 26: 37–56.

Kyerematen RAK, Sæther OA, Andersen T (2000): A review ofthe Rheotanytarsus pellucidus group (Diptera: Chironomi-dae). In: Hoffrichter O, ed., Late 20th century research onChironomidae: an anthology from the 13th InternationalSymposium on Chironomidae, Aachen, Shaker Verlag, pp.147–170.

Langton PH (1994): If not ‘filaments’, then what? Chironomus6: 9.

Pinder LCV, Reiss F (1983): 10. The larvae of Chironominae(Diptera: Chironomidae) of the Holarctic region. Keys and diagnoses. In: Wiederholm T, ed., Chironomidae of theHolarctic region. Keys and diagnoses. Part 1. Larvae. Entscand Suppl 19: 293–435.

Pinder LCV, Reiss F (1986): 10. The pupae of Chironominae(Diptera: Chironomidae) of the Holarctic region – Keys and diagnoses. In: Wiederholm T, ed., Chironomidae of theHolarctic region. Keys and diagnoses. Part 2. Pupae. Entscand Suppl 28: 299–456.

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Sæther OA (1990): A review of the genus Limnophyes Eatonfrom the Holarctic and Afrotropical regions. Ent scandSuppl 35: 1–135.

Sæther OA (1977): Female genitalia in Chironomidae and otherNematocera: morphology, phylogenies, keys. Bull Fish ResBd Can 197: 1–211.

Sæther OA (1980): Glossary of chironomid morphology termi-nology (Diptera: Chironomidae). Ent scand Suppl 14:1–51.

Sæther OA, Kyerematen RAK (2001): Towards a phylogeny andzoogeography of the genus Rheotanytarsus Thienemann etBause, 1913 (Diptera: Chironomidae). Tijdschr v Ent 144:73–117.

Spies M, Reiss F (1996): Catalog and bibliography of Neotrop-ical and Mexican Chironomidae (Insecta, Diptera). Spixi-ana Suppl 22: 61–119.

Sublette JE, Sasa M (1994): Chironomidae collected inOnchocerciasis endemic areas of Guatemala (Insecta,Diptera). Spixiana Suppl 20: 1–60.

Sublette JE, Stevens LE, Shannon JP (1998): Chironomidae(Diptera) of the Colorado River, Grand Canyon, Arizona,USA, I: Systematics and ecology. Great Basin Nat 58:97–146.

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Documents

Rheotanytarsus Thienemann et Bause (Diptera: Chironomidae) from Central America and Mexico