Characoids_Parte1.pdf

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Actually, this will probably not alwaysbe the case, and the reader must

be prepared for some falseleads. The impossibility of identifyinga particular

species may be due to the foJlowing: certain keys are surely imperfect,

suffering from some defect wbich can only be detected after several tests;

certain exceptions t9 the presence or absence of a character may cause

difficulties, although they should be mentioned in the key when known;

and the whole group is still imperfectly known and it may be, cbieftyif the

species is small and comes from some remote area, that the unidentifiable

specimen has never been scientificallydescribed (a so-called new species).

The characoids now number more tPan 1200species (inc1uding200 or so

Mrican ones), and, based on past experience, in every large collecting

sample 5-10 of the species can be expected to be new.

KNOWLEDGMENTS

The author wishes to extend bis thanks to the persons who have gready

contributed to the book:

Dr. Warren Burgess, who had the diff icult task of making the author s

language readable by English-speaking people, and the people whose

remarkable photographs provide the indispensable illustrations, principally

Dr. H. R. Axelrod and the late Harald Schultz, in whose memory this book

is dedicated.

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able of ontents

(

Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Acknowledgments 5

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Part 1: The African FamUies. . . . . .. . . . . .. . . . . . . . . . . . . . . . . .. .17

Key to the African Families . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Family Hepset idae (African pike-l ike characoids) . . . . . . . . . . .17

Family Alestidae (African tetras). . . . . . . . . . . . . . . . . . . . . . . . .18

Subfamily Alestinae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Subfamily Hydrocyninae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Family Citharinidae (citharinids) . . . . . . . . . . . . . . . . . . . . . . . .54

Subfamily Citharininae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

Subfamily Distichodinae . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58

Subfamily Ichthyborinae . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82

Part 2: The American Characoids other than the Characidae. . . . .95

Key to the American Families . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95

Family Erythrinidae (trahiras) . . . . . . . . . . . . . . . . . . . . . . . . . .98

Family Ctenoluciidae (South American pike-characoids). . . .103

Family Crenuchidae. . . . . . . ; _. . . . . . . . . . . . . . . . . . . . . . . . . 106

Family Characidiidae (South American darters ) . . . . . . . . .111

Subfamily Characidiinae. . . . . . . . . . . . . . . . . . . . . . . . . . . .114

SubfamilyElachocharacinae .119

Subfamily Geisleriinae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Family Lebiasinidae (pencilfishesand pyrrhulinins) . . . . . . . .123

SubfamilyLebiasininae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 23

SubfamilyPyrrhulininae . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Family Anostomidae (headstanders and leporins) . . . . . . . . . .150

SubfamilyLeporellinae . . . . . . . . . . . . . . ; . . . . . . . . . . . . .151

SubfamilyAnostominae. . . . . . . . . . . . . . . . . . . . . . . . . . . . .151

Family Hemiodidae (hemiodidsand their relatives) . . . . . . . .190

Subfamily Hemiodinae .190

Subfamily Parodontinae 202

Family Curimatidae (curimatas). .210

Subfamily Chilodinae 211

SubfamilyP rochilodinae . . . . . . . . . . . . . . . . . . . . . . . . . . . .214

Subfamily Curimatinae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

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Subfamily Anodinae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

Family Gasteropelecidae (hatchetfishes) 243

Family Serrasalmidae (pacus, silver dollars and piranhas) . . .251

Subfamily Myleinae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .251

Subfamily Serrasalminae . . . . . . . . . . . . . . . . . . . . . . . . . . . .275

Subfamily Catoprioninae. . . . . . . . . . . . . . . . . . . . . . . . . . : .294

Part 3: The American Tetras and Characins (Family Characidae)

.295

Subfamily Agoniatinae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298

Subfamily Rhaphiodontinae . . . . . . . . . . . . . . . . . . . . . . . . . 299

Subfamily Characinae . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .302

Subfamily Bryconinae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330

Subfamily Clupeacharacinae 346

Subfamilies Paragoniatinae and Aphyocharacinae . . . . . . .347

SubfamilyGlandulocaudinae .351

Subfamily Stethaprioninae . . . . . . . . . . . . . . . . . . . . . . . . . . 366

Subfamily Tetragonopterinae . . . . . . . . . . . . . . . . . . . . . . . .371

Subfamily Rhoadsiinae 538

Subfamily Cheirodontinae and allied genera . . . . . . . . . . . . 543

Undescribed or unidenti fied species . . . . . . . . . . . . . . . . . . . . . . . . .609

Glossary of technical terms . . . . . . . . . . . . . . . . . . . . . . . . . .611

Bibliography I: Africa 621

Bibliography 11: South America . . . . . . . . . . . . . . . . . . . . . . . . . . . .642

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .647

INTRO U TION

Onee upon a t ime, an Mrican fresh-water fish decided to beeome a

eharaeoid.

This happened long ago, in the Mesozoie (70-175 millions of years?)

when eonditions were favorable. Volcanismwas intense, working profound

modificationsof the earth. Our fish lived iJ) a mythical land, called Gond-

wanaIand, formed by the united continents of Mrica and South America.

They were soon to be separated, owing to a gigantiebreak which had just

started, forming a ehain of great lakes.A similar processis actualIyin action

in Mrica today; the new break starts with the Red Sea and is prolonged by

the Rift VaIleyforming the Great Lakes of Africa (Tanganyika, Malawi,

Victoria, ete.).

Sueh lakes are the most suitable plaees to alIowwhat is calIedexplosive

evolution to oecur because they offer the greatest ecologica1opportunities

to the species.These species are able to oecupy a multitude of empty spots

sueh as rocks, sand, grass-beds, bottom, surfaee, and so on, or potentiaI

so-calIed eeological niehes. Another possible cause of rapid and active

speeiation in Great Lakes, as eontrasted with the normal evolution in

adjaeent rivers, may be the laek of important f ish predators (sueh as

Hydrocynusor Lates in certain Mrican lakes)whieh, when present, restrain

the diversificationof the species.

The ambitious fishmentioned at the beginning ofthe story (whichis not

a fairy-tale but a hypothesis based on eertain welI established facts), was

probably a species resembling what we now calI a gonorynchiform. That

smalI group of partIy fresh-water fishes, mostly Mrican, with Kneria

romeria and others, seems indeed to have some pre-ostariophysine

features.

An ostariophysine fish (eharaeoids were apparently the first ostario-

physans, although certain authors believethat the catfishesaremore ancient)

is eharacterized by at least two features: a chain of ossic1es,calIedWeber s

ossic1es,uniting the gas-bladder with the internal ear and permitting the

hearing of high-frequency sounds; and a chemical alarm system, telling the

sehooling fish that one of its eongeners has been attacked by a predator.

These twoadaptations are supposed to be useful to fishesliving in schoolsin

fresh-water biotopes (which is the casein inost characoids and cyprinoids).

8

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upheaval ofthe Andes, as if the westem coastof South America had abutted

against a static block in its course to the west. This in turn caused the

formation of the Amazon basin, the greatest of the world, which offered the

best opportunities to a young, opportunistic group of fishes.

These two reasons explain why the Neotropica1 characoid fauna repre-

sents, in number of species, about 80% of the total, and the African

( Ethiopian ) fauna consequently only 20%, with 11and 3 families res-

pectively, according to certain modem authors.

On each side of the Atlantic Ocean, similar ecological pressures deter-

mined a parallel evolution. Certain evolutionary convelgences are worth

mentioning:

The African pike-characoid ps tushas its counterpart in the

American

Acestrorhynchus.

The large African alestids (except

Hydrocynus)

strongly parallel the

American Bryconinae, whereas the small alestids are scarcely discemable

from the numerous American tetras.

Hydrocynus,

a modification of an alestid toward predation, has dose

similarities with the Neotropical

Hoplias

or

Erythrinus.

Most of the Citharinidae are convergent with certain Hemiodidae and

Curimatidae (two rather dosely related American families), whereas

some others, very smalland bottom-living fishes

Nannocharax

and allies),

are strikingly similar to the Neotropical Characidiidae.

1n the above cited examples, only knowledge of the origin, or the study

of anatomical details, can tell the non-specialist whether he is dealing with

an African or an American line, which diverged from each other so many

millions of years ago.

Hepsetus,

the most primitive characoid according

to T. Roberts (forming the family Hepsetidae), has an accessoryectoptery-

goid bone and a canal into the supraoperde. These characters are not shared

by any Neotropical characoid, even the Ctenoluciidae which are apparently

the dosest group. The citharinids have ctenoid scales(except for onegenus),

numerous ventral rays, pharyngeal bags and other features which do not

exist (at least together) in American families. Finally, the alestids differ

from their dosest American relatives, the Characidae, in having no rhino-

sphenoid, a bony tube endosing the olfactorynerve, a toothless, paddle-like

maxilla, and other characters.

1t has been pointed out above that the evolution of the characoids, chiefty

of the Neotropical ones, resembles that of the more recent cichlids from

certain African lakes.Both groups, each with a different time scalehowever,

entered new biotopes and exploited all of their possibilities.

1ndeed, mos of the adaptations enumerated by Fryer and Iles (1972)

conceming the African cichlids are found in the characoids. They practice

commensalism,mimicry,shoaling (alsocalledschooling),migration, burrow-

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Alestidae, Serrasalmidae, Crenuchidae and even in one curimatid genus,

whereas care of the young appeared in at least three lines, certain Erythrini-

daeand Serrasalmidae,and certain Pyrrhulininae in the familyLebiasinidae.

The above enumeration of their intricate adaptations helps to explain

why the systematics of the characoids has long been, and stilIis, a difficult

task. They were recognized as a homogeneous group only in 1844by two

German ichthyologists, MlIer and Troschel. The Viennese Kner and his

student Steindachner (between 1858and 1915)folIowedby accurately des-

cribing a number of species without paying much attention to their c1assi-

fication. It remained for one of the best ichthyologists of alI times, Carl H.

Eigenmann, to undertake, in the U.S., a natural c1assificationof the South

American groups. His principal monographs were issued between 1910and

1927.He wasfolIowedby his student, George S.Myers, the still veryactive

father of the characologists, who in turn handed the torch down to his

own students, J. Bhlke, S. Weitzman and several others, forming a chain

of interest which is presently stilI growing.

Recentlya series of anatomical studies by S. Weitzman, T. Roberts, and

Others helped specify the systematic position of several critica1 groups,

which led to the recognition ofmany familieswithin the suborder (a division

which could never have been accepted in Eigenmann's time) and revealed

the importance, as welI as the complexity, of the characoids, presently

considered as a key-group among the teleosts.

The first authoritative division ofthecharacoids into several families (16)

was done by S. Weitzman, in Greenwood et aI. (1966).The arrangement of

the families in the present book takes into account that c1assification,as

modified by Gry (1972),with a few alterations from the 1972order.

As compared with Weitzman's c1assification, the present one is as

folIows:

ing in sand, and so on. They havedevelopedthree means ofcommunication,

namely sounds, chemicals, and recognition marks (mostly on humeral

region.and caudal pedunc1e, as welI as on dorsal and adipose fins). They

have, in certain cases, elaborated or evolved breeding habits such as the

care of the young aspracticed by the piranhas. Finally, they have developed

an array offeeding habits, which is largely comparable to that ofthe cichlids,

inc1uding scale eating or fin biting, as well as other adaptations which are

almost unique among teleosts, such as flight (hatchet-fishes) or group-

predation (piranhas).

Owing to the millions of years of evolution at the disposal 0f the

characoids, these adaptations ocurred more than once and in different

phylogenetic lines. This resulted in an extremely confusing complexity of

groups. It is often difficult to telI from a character shared by different forms

the role of true phylogeny (common origin) and of convergency (different

origin). That is how a generalized body-shape, like that of a salmon or a

trout for example, is to be seen at the same time in Brycon, Salminus and

Astyanax, which originated from three different evolutionary lines

(although in the same family).

Evolution of a predatory existence, that is predation mostly on fishes,

appeared at least eight times in completely different lines:

Hep~ etus,Hydro-

cynus

and certain Citharinidae in Africa,

Ctenolucius

et aI.,

Erythrinus

et aI.,

Acestrorhynchuset aI. and several other Characinae, not forgetting the

piranhas (Serrasalmidae) in South America.

The plant-eaters belong to at least three families, namely Citharinidae,

Anostomidae and Curimatidae. But some members of other groups, for

example Deuterodon in the Tetragonopterinae, and several others, also

developeda herbivorous habitoThe same is true for the limnivorous species,

found in the Citharinidae as welIas in the Curimatidae, the Aufwuchs -

eaters, which nibble food from rocks or falIentrees (two or three families),

the plankton-feeders (at least two families), and the specialized forros

referred to above. Scale-eaters appear in two families, Characidae and

Serrasalmidae, and the fin-biters also in two families, Citharinidae and

(probably) Serrasalmidae.

Several species are adapted to life in river torrents. They belong to three

families, Citharinidae (with Nannocharaxet al.), Characidiidae (with Chara-

cidium et aI.) and Hemiodidae (with Parodonet al.).

A ventral keel appeared in several subfamilies of the Characidae Trip-

ortheus, Gilbertolus,Gnathocharax, Pseudocorynopoma

and so on), and also

in certain Curimatidae, as welIas in the Serrasalmidae, culminating, in the

Gasteropelecidae, in a complex of adaptations permitting flight a few inches

above the water surface.

FinalIy, sexual dimorphism is evident in the Characidae as welI as the

S. WEITZMAN in GREENWOOD

et a . (16 families)

(1) CHARACIDAE

(2) ERYTHRINIDAE

(3) CTENOLUCIIDAE

(4) HEPSETIDAE

(5) CYNODONTIDAE

(6) LEBIASINIDAE

(7) PARODONTIDAE

(8) GASTEROPELECIDAE

(9) PROCHILODONTIDAE

PRESENT ARRANGEMENT

(14 families)

(2) ALESTIDAE; (6) CRENUCHIDAE;

(7) CHARACIDIIDAE; (13) SERRASAL-

MIDAE; (14) CHARACIDAE

(4) ERYTHRINIDAE

(5) CTENOLUCIIDAE

(1) HEPSETIDAE

RHAPHIODONTINAE, a subfamily of the

CHARACIDAE

(8) LEBIASINIDAE

PARODONTINAE, a subfamily ofthe

HEMIODIDAE

(12) GASTEROPELECIDAE

PROCHILODINAE, a subfamily of the

CURIMA TIDAE

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-

10) CURIMATIDAE

11) CURIMATIDAE including

PROCHILODINAE, CHILODINAE and

ANODINAE)

9) ANOSTOMIDAE

10) HEMIODIDAE including

PARODONTINAE)

CHILODINAE, a subfamily of the

CURIMA TIDAE

DISTICHODINAE, a subfamily of the

CITHARINIDAE

3) CITHARINIDAE including

DISTICHODINAE and

ICHTHYBORINAE)

ICHTHYBORINAE, a sub family of the

CITHARINIDAE.

Part I

The African Families

11) ANOSTOMIDAE

12) HEMIODONTIDAE

13) CHILODONTIDAE

14) DISTICHODONTIDAE

15) CITHARINIDAE

KEY TO THE AFRICAN FAMILIES

16) ICHTHYBORIDAE

a. Scalescycloid; teeth usuallywelldeveloped, not movable; joint betweentwo sides

of mandible with some interlocking device,movable; no pharyngeal bags .

b. Predaceous fishes armed with strong canines; maxilla entirely toothed; an

accessory ectopterygoid bone; a large supraopercle bearing a lateral line

canal HEPSETID E

bb. Omnivorous fishes usually with incisifo rm and molariform teeth, rarely

piscivorous and with canines as in the subfamily Hydrocyninae, with a s ingle

genus); maxilla never toothed; no accessory ectopterygoid bone; no

supraopercle LESTID E

2 subfamilies)

aa . Sca les ctenoid except in

Citharinus

which is a bream-like fish very different

from

Hepsetus

or from an alestid); teeth usually small, often movable; joint

between two sides of mandible simple, sometimes ankylosed; pharyngeal bags

present

. . .

CITHARINIDAE

3 subfamilies)

The evolutionary importance of the group will be conspicuous, i t ishoped,

in the body of the book, which will deal successively wi th the African and

American characoids, ending, in a third part, with the most successful

Neotropical group, the Characidae.

Family Hepsetidae

frican Pike like Characoids

Hepsetusodoe

formerly called

Sarcodacesodoe

is the singlerepresentative

of thefamily. Its external resemblancewithan cestrorhynchusbyconvergent

evolution, is striking. However, an examination of the finer structures of its

skull reveals a number of differences. Hepsetus according to Roberts, is

more closely related to another South American group, the Ctenoluciidae,

but with many more primitive features accessory ectopterygoid bone,

flattened cranial roof, large canal-bearing supraopercle, and so on) which

make it probably the most primitive characoid. The African pike lives in

almost alI rivers of the tropical area, with the exception of the Nile basin.

It is a fish-predator, welI armed with strong, caniniform teeth, similar to

those of Hoplias cestrorhynchus and the like. The maxillary bone is

* This key,likeali other keysin the book, isfor identificationpurposes only. It isnot

intended to reflectrelationships.

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entirely toothed as in most predators. According to the author s own

experiencein Mrica, it is a good game-fish, behavinglike a European pike,

putting up a goodfight. It reaches 30em in length and is edible. Its color is

brownish with indistinct bars on the body and small spots on the fins; its

adipose fin is bright orange and black, apparently forming a recognition

signal.

Svensson, as well as Johnels, has reported that Hepsetus spawns somewhat

in the manner of the anabantids. A nest of floating foam is made by the

spawning pair and the eggs (which are aft erwards guarded by both paren ts

or one parent only) are deposited in it.

Family Alestidae

frican etras

The Alestidae are the Mrican counterparts of the Characidae, and there

is little doubt that the two groups have the same originoOne example will

show how similar they are. A new genus and species Pellegrininahetero-

lepis) wasonce described asa newMrican form dose to Alestesand Brycinus,

because the specimen studied wasthought to come from some part ofWest

Mrica. A more critical evaluation revealed afterward that the label on the

bottle was incorrect and that the fish was a well-known South American

Chalceus.

Despite the general resemblance between the two groups (which led

several ichthyologists to recognize on1yone family from both sides of the

Atlantic Ocean), the Alestidae have the following characteristics in con-

trast to those of the Characidae (at least those characids which most

resemble the alestids, namely the Bryconinae): no rhinosphenoid (a small

bone in front of the orbitosphenoid, present in Brycon); olfactory nerve

endosed in a bony tube formed by the orbitosphenoid and the lateral

ethmoid; lateralline, when present, very low, the number of scalesbetween

lateralline and ventral fin Deverexceeding 3 (usually 2). In the Alestinae,

the maxillary bone (more or less covered by the first infraorbitals) is tooth-

less, usually paddle-like with a rounded contour and a thin pedicel (like a

music note). The premaxillarybone has a characteristicpedicel-likeposterior

process extending to themaxilla,which is rather firmlyunited to it; the inner

premaxillary teeth are invariably four in number (apparently a primitive

number, also to be found in the American Hemibryconini), andmolariform

(except in the small species), usually with the crushing face excavated, the

posterior border rounded, multi-cuspidate, and the anterior one with two

prominent cusps or points. On the mandible there is usually a pair of small

conical teeth behind the main series.

18

.-.....

In the Hydrocyninae, which are ichthyophagous predators derived from

some Alestes, the powerful jawsare armed with a single series of very acute

caniniform teeth; it is believed that these teeth correspond to the outer

series of the alestins. Another pecu1iarityofthis group is the type ofmiddle

joint between the two parts of the mandible. It is a bolted hinge, whereas

that of the alestins is said to be a fluted tenon. Otherwise, as concems

the general organization, a Hydrocynusdoes not ditfer essentially from an

Alestes.

Accordingly, the family Alestidae will be split into two groups at

the subfamiliallevel:

a. Teeth in 2 rowson the upper jaw (three rowsin onegenus),the inner row usually

composed of molariform teethj omnivorous species

. . .

ALESTINAE

aa. Teeth in 1 row on both jaws, caniniformj ichthyophagouS species

... HYDROCYNINAE

SUBFAMIL Y ALESTINAE

frican etras

Quite artificially, one may divide the alestins into two groups, Alestini

and Petersini, which could be calledtribes. The Petersini looklike the young

of the Alestini and constitute what are properly called the Mrican tetras.

They ditfer from the Alestini not on1yby their small size (frequently in

correlation with the reduction of the lateralline), but alsoin other regres-

sive characters. The inner teeth of the upper jaw are no longer excavated

and molariform, but have retained a single, pluricuspidate cutting edge, and

the inner mandibulary conical teeth are often lacking. Some alestins, the

so-called longipinnis-group,form a SOftoftransition between the twogroups,

the species being small and the molariform structure of their teeth scarcely

evident.

Tribe Alestini

The presentauthor recognizes3 generadiagnosedby the followingkey:

a. An adipose l id covering at least par t of eye; a lways a fontanel ; sca les with

radiating radii which are never anastomosed.

b. Premaxillary teeth triserial; 3 scales between lateral line and ventral fin;

dorsal fin well infront ofmidbody, filamentous in adult male j body deep (depth

2.8-3.5nstandardength) . . . Bryconaethiops

bb. Premaxillary teeth biserialj It-2 scales between latcralline and ventral finj

dorsal fin at midbody or even behind, not filamentous; body elongate (depth

3.25-5nstandardength) . . . A/estes

l ia .No adipose l idj usual ly no fontanel , except in a few species B. leuciscus,

B. /ongipinnis,B. chapen ,B. opisthotaenia)

r ad ii of the scal es usually

anastomosed .. .

Brycinus

.

. ,., :> Py. Va ni el

I.C -

I 19

C po~rltll.;,- .P

\ 8 .. .

~9.000

_ Manaus. Amazona.


12/127

NUS RYCQN ETHIOPS

This genus includes a few species whieh ehange eonsiderably during

growth, eertain of the adults being seareely identifiablewith the young. By

the time they reaeh 200 mm in length they are usually very deep, very dark

sometimes almost blaek , and the filaments of the dorsal fin of the males

reaeh the caudal finoThe group isat onee reeognized by the 3 seriesof teeth

on the upper jaw it is somewhat like modified

Alestes

just as

Creagrutus

in

the American tetras, looks like a modified Hemibrycon but is urgently in

need of a revision at the species leveI.

The two or three speeies, B. microstoma B. boulengeriand perhaps B.

macropswhieh, if valid, is mueh rarer , are mostly from the Congo basin

including Ubanghi although some species are found in Cameroon and

Gaboon.

Alestesmacrophthalmusis a southem form from the Congo and Gaboon,

A. liebrechtsiiisrestricted to the C~ngo basin, and the small A. stuhlmanni

seems to be an endemic form from East Mrica.

Exeept for some red eolor on the caudal fin in eertain forms, species of

Alestes are usually uniform silvery, without eharacteristie markings.

Bryconaethops sp. Photo by Dr. J. Gery.

NUS

LESTES

A few species, namely Alestes dentex A. baremose A. macrophthalmus

A. liebrechtsiiand A. stuhlmanni have rather reeently been separated from

the bulk ofthe Alestes-like species on the basis of anatomieal details sueh as

adipose lid, fontanels, ete. They are usually large up to 45 em , elongate

speeies inhabiting large rivers. Some are of eeonomie importanee. Aleste.~

dentex and A. baremose from the Nile, Niger, Tehad, Senegal, ete., are

sibling species, being separable only by the number of gill-rakers.

A/estes baremose and A. lebrechts photos by Dr. J. Gery ; A.

dentex

after Boulenger, 1909 ;A.

macrophtha/mus

holotype after

Boulenger, 1909 .

2

2


13/127

GENUS BRYCINUS

This genus is an aggregate of species in which one may recognize five

groups. Some of these could, perhaps, be ranked as subgenera, although

overlapping of characters is frequent; the others are quite artificial

assemblages. The Brycinus macrolepidotus

-

group (1), which contains the

type species of the genus Brycinus B. macrolepidotus and a few other

species, is characterized by the large size (up to 50em), straight dorsal

profile, dorsal fin far behind mid-body, and overhanging snout. The other

four groups, which have dissimilar characters, may be recognized as

foUows:

a. Interorbital usually less than 3 times in length of head; caudal peduncle high

(its depth 1.0-1.5 in its length).

b. 16-28 gill-rakers on lower arch (fontanel always absent; scalesusually with

anastomosed radii) . . . (2) Brycinus nurse-imberi-group

c. Dorsalf ins lightlyinfrontofmid-body . . .

B. nurse

cc. Dorsal fin at mid-body or slightlybehind . . . B. imberi-group6-7spp.)

bb. 11-18 gill-rakers on lower arch (fontanel present or absent; scales with or

without anastomosed radiO.

d. Bodydepth3.5-3.66in standardlength; sca1esbetweendorsalfin and

lateral line; sca1eswithout anastomosed radii; no fontanel; dorsal fin

usually behind mid-body . . . (3)B. rutilus-group(2spp. ?)

dd. Body depth 2.3-3.5 in standard length; 5-6sca1esbetween dorsal fin and

lateralline; sca1eswith anastomosed radii; sometimes a fontanel; dorsal

fin usually at mid-body or in front of mid-body

. . . (4)

B.longipinnis-group

(8-9spp.)

aa. Interorbital 3.0-3.5 times in length ofhead; depth ofcaudal peduncle 1.5-2.0 in

its length (fontanel alwaysabsent; scaleswithout anastomosed radii)

. . .

(5)

B.

humilis-group

(4 spp. ?)

(1) The Brycinus macro/epidotus-group

The large species belonging to the nominal genus Brycinus have a dis-

tinctive shape, the straight snout (which continues the long, also straight,

predorsalline) overhanging the mandible. The smallest of the six induded

species, B. brevis(225mm) from Nigeria and the Gold Coast, is also the

deepest (body depth 2.75 to 3.0 in standard length), with few lateral line

sca1es(21-23),and is a uniform color,

Brycinuscarmesinus

isvery dose to it.

The four other species are more elongate(body depth 1.5 to 4.0 in the

standard length). Two of them, B. grandisquamisfrom the Congo basin and

B. batesiifrom South Cameroon, attain 26 em in length and can be easily

recognized thanks to a conspicuous spot on the end of the caudal pedunde.

They have, respectively, 23-27 and 28-29 lateral line scales, and 13-14

versus 15-16 anal rays.

22

:

.

~~

..4

jj-

Brycinus sp., juvenlle. Photo by G. Timmerman.

Brycinus macrolepidotus the type species ofthe genus, inhabits a large part

of Mrica from the Nile to the Congo. It usually has a broad dark longi-

tudinal bando

Brycinus rhodopleura

is its represen~tive in Lake Tanganyika,

dif fering only in the number of lateralline scales (22-26 sca1esin B. macro-

lepidotus

versus 28 29 in

B. rhodopleura .

They reach, respectively, 42 and

30 em in length.

(2) The Brycinus nurse-imberi-group

Brycinus nurse (type species of the genus BracJzyalestes not used much

nowadays) and the Brycinus imberi-group (with B. imberi B. jacksoni

B. affinis B. taeniurus B. kingsleyae and B. bimaculatus are medium-sized

(100-230 mm) alestins with the dorsal fin at mid-body or thereabouts and

16-28 gill -rakers (usual ly less than 18 in the Other groups).

Brycinus nurse isthe onlyspecies inthis group to have the dorsal fin slightly

in advance ofmid-body, and it is also the largest (230 mm); it has the same

geographical distribution as B. macrolepidotus pIus Lakes Victoria and

Rudolf. The caudal fin and part of the ventral and anaI fins are usually red;

humeral and caudal spots are present.

Species ofthe B. imberi-group strictly speaking have the dorsal fin inserted

at mid-body or sl ight ly behind. B. kingsleyae and B. taeniurus from South

Cameroon, Gaboon and Chiloango are immediately recognizable by the

dark lateral band beginning behind the dorsal fin leveI and ending on the

middle caudal rays. Brycinus kingsleyae has a humeral spot (Iacking in

B. taeniurus

and a shorter anaI f in (12-13 branched rays versus

15 17 .

23

...


14/127

B. imberi of which curtus bequaerti and jacksoni are possibly synonyms)

f rom Cameroon to Kasai , B. bimaculatus from the upper Congo, and B.

affinis

an endemic species from East Mrica, are mostly distinguished by

their color pattern.

B. imberi

usual ly has a conspicuous humeral spot and a

broad caudal spot ending on the caudal rays; B. bimaculatus has the same

caudal spot but it i s restricted to the caudal pedunde and also has a lateral

spot much farther back at the leveI of the end of the dorsal fin);

B. affinis

has the same humeral spot as

B. imberi

but has no caudal spot at all.

elongate body.

B. rutilus

is a large form up to 32em) with the finssome-

times bright vermilion hence its name). lt inhabits the same regions inWest

Africa as B. macrolepidotusbut is nowhere captUred with it a vicarious

species). B. stolatusfrom the Congo is a small ?), poorly known species

without color marks.

.

4) The Brycinus longipinnis group

This quite unnatUral group forms a sort of transition with the small

alestins called tribe Petersini. Most of the species are small. They some-

times have a fontanel and, at least when young, their inner premaxillary

teeth are more compressed than in typical Brycinus. However, a dose

examination reveals a pair of smalI shoulders in front of the largest teeth,

which is almost the only character which distinguishes them from the next

tribe.

B. leuciscus

from the Senegal and Niger basins where it is calIed

tineni

and is of economic importance), has long been confounded with the young

of B. nurse but it has yelIowfins instead of red. Another species, more

recently described, is alsovery dose. This isB. dagetifrom the Tchad basin,

which differs from B. nurse in being matUreat half the size of the latter

species,as welIas by the number of gilI-rakers. It seems to be the sibling of

B. nurseand might welIbe dassified together with B. leuciscuswithin the

B. nurse group.

The

B.longipinnis group

strictly speaking isin need ofrevision like other

Brycinus groups). The folIowing key will aid in distinguishing the species:

a. Not more than 30 lateralline scales 18-21 branched anal rays; dorsal fin filamen-

tous inmale; caudal band present) . . . B.longipinnisB. chaperi

and an undescribed forro

from the Ivory Coast West

Africa, plus Equatorial

Africa for

B. chaperi

on1y

?

3 The

Brycinus rutilus group

This smal l group dif fers from the preceding one mostly in having fewer

gil I-rakers and from the next one by the st ructUre of the scales and the more

B;ycinus bimaculatus hoJotype after Boulenger, 1899 and nurse

photo by Dr. J. Gery .

aa. 32-37

lateralline scales.

b. 16-21 branched anal rays.

c. An elongate caudal spot; 16-17 branched anal rays; 33 lateralline scales

. . . sadleriendemicspecies

from Lake Victoria

cc. Caudal spot broad or absent; 17-21 branched anal rays; 33-37 lateralline

scales.

d. A broad caudalspot; dorsalrays filamentous in male, marked with a black

ba r; 33-35 lateral l ine sca les . . . intermediusSouth

Cameroon

dd. Body andfins plain; 371ateralline scales

.. . essmanniSouth

Cameroon

bb. 24-26 branched anal rays body and fins plain; 32 lateralline scales

. . . tholloniCongobasin

r

24

25

. .


15/127

B. longipinnis

and

B. chaperi,

probably sympatric in West Mrica, are the

best known alestins among aquarists. The two species are difficu1tto teU

apart, especiallywhen one has to dea1with young individuaIs. As a role,

B. chaperi

has slight1ymore lateralline sca1esthan

B. longipinnis 28-30

versus 26-27), as welIas a longer snout, shorter maxilIary bone, broader

i nt erorbital and deeper caudal pedunde. I ts dors al f in is also i ns ert ed

farther back th an that of B. longipinnis,being at mi d- body or s light1y

behind versus slight1yin front of mid-body).

5)

h Brycinus humi/is-group

The four species.

B. humilis, B. abelt~ B . lateralis

and

B. opisthotaenia

are

alsovery dose to certain species of

Micralestes.

They are smalI maximum

size 150mm), with few scales 24-34) and few branched analrays 12-17 .

Brycinus opisthotaenia,

from South Cameroon and Gaboon, is the largest

s peci es and has r et ai ned m any Brycinus macrolepidotuscharacters. It. is

remarkable in having contact tuberdes similar to those on the snout and

head of m ature m al e barbs and species of

Labeo

over t he whol e body i n

bot h s exes . Nothing is known about the s ignif icance of thes e t uber des

calIednuptial tuberdes or pearl organs in the barbs). Like

B. opisthotaenia,

B. lateralis

has a black lateral band after preservation) but no humeral spot.

I t i nhabits K at anga and A ngol a up t o the Zam bezi R iver , and dif fers by

havingmore scales 30-33versus 24-27lateral line scalesin

B. opisthotaenia .

B. humilis from Angola and B. abeli from Ubanghi have a horizonta11y

elongate caudal s pot; t hey dif fer in t he s am e w ay as t he above, having

respectively 30 and 24-26 lateral line sca1es.

ribe etersini

5mall African Tetras

Thi s group of about 60 s peci es has r ecent 1ybeen r evised by PolI . He

adm it ted 16 gener a as val id, i nduding s ome proposed by H oedeman in

195.6which are questionable. It looks as if the group is oversplit, which

seemsevidentwhen onecomparesthe Petersiniwith their American counter-

part the Hemibryconini. The latter group has 12or 13genera with about 80

species. However, the evolutionary conditions were not exact1ythe same,

owing to the absence in South America, for example, of the barbs, which

compete severelywith the Mrican tetras. Here on1ya part of the 16genera

actually 18 induding Ladigesiaand Virilia, which were not described at

the time of PolI s revision) will be accepted as diagnosed by the following

key:

8rycinus humilis,

hOlotype after Boulenger, 1909 and 8.

rutilus

photo by Dr. J. Gery .

aoTeeth multicuspidate; two premaxillary series.

b. Predorsalline scaled; no outward-directed teetho

c. A pair of conical or rarely) cuspidate teeth behind the main mandibulary

series.

d. Teeth usually with more than 3 cUSPSo

e. More than 4 outer premaxillaryteeth total lateralline usually complete)

.. .

I)

Micralestes

eeo4 outer premaxillary teeth, 2 on each side lateral line complete or

incomplete) o o o 2)Phenacogrammus

This genusmay be split

into 3or 4groups)

dd. Teeth tricuspidate lateralline incomplete; 4 outer premaxillary teeth)

o. .

3) Tricuspidalestes

cc. Conical teeth behind the main mandibular seriesusually absento

f. Scalesof fiank and abdomen of equal size; 4 or 6 outer premaxillary

teeth 2-3 on each side); 8-11 mandibular teeth.

g. Posterior fontanel present; mandible not prominent lateral line

completeor incomplete) . . o 4)Hemigrammopetersius

This genus may be split

i nt o 4 o r 5 g ro up s o f

species)

26

27


16/127

gg. Posterior fontanel absent, at least in adults; mandible very pro-

minent (lateralline complete) .. . (5) Petersius

ff . Scales of flank much larger than those of abdomen; 8 outer pre-

maxiUaryteeth; 16-20mandibular teeth

. . . (6)

Arnoldichthys

bb. Predorsalline naked; teeth partly outward-directed

. . . (7) Ladigesia

aa. Teeth conical, in one series(lateralline incomplete).

h. Scalesnormal; mouth cIupeoid

. . . (8) Clupeocharax

hh. Bodynaked,withoutscales;mouthnormal

. . . (9) Lepidarchus

a. Pair of small teeth behind main mandibulary series conical, without cusps; no

more than 7-9 cusps in the broadest teeth.

b. Usually less than 29 lateralline scales.

c. No black longitudinal band; body depth 2.6-2.9 in standard length

. . . M. holargyreus Congo

basin)

cc. A bIack longitudinal band, more or less complete; body depth 2.9-4 in

standard length.

d. Eye2.6-3.3in lengthof head (adult); more than 50mmin standardlength.

e. 22-24 Iateralline scales.

f. Longitudinal band beginning at dorsallevel; head 3.7-3.9in standard

length; 15-16branched anal r ays . . . M.

stormsi

(Congobasin;

verydifficultto separate

fromM. humilis

ff. Longitudinal band complete; head 3.95-4.1 in standard length;

16-18branchedanalrays . . . M.vittatus(Lake

Tanganyika)

ee. 25-29 lateralline scales(longitudinal band complete).

g. Lateralline complete.

h. Length of head 3.4-3.8 in standard length.

i. ScalesofIateraI line with bIackspot at base; 25-27 lateralline

scales . . . M.

humilis

Tchad,Congo

and Zambezi Rivers)

i i . Sca les of late ra ll ine not marked; 24-25 Iaterall ine scales .

. . . M.

voltae

(upper Volta

basin; difficult to teU from

M. elongatus

hh. Length of head 3.75-4.1 in s tandard length .

j. 18-19 branched anal rays; tip of dorsal fin black (25-26

l atera ll ine sca le s) . . . M. occidentalisWestMrica)

j j . 16-17 branched anal rays; tip of dor sal fin hyaline

. . . M.

sardina

(upper Congo

basin)

gg. Lateral line usuaIIy not quite complete, lacking a few pores on

caudal peduncIe; 16-19 branched anal rays; length of head 3.4-4

in standard length (speciesof West Mrica).

k. Tip of dorsalfin black; body depth 3.45-3.95 in standard

length . . . M.elongatusupperVolta)

kk. Tip of dorsal fin hyaline; body depth 2.8-3.3 in standard

length . . . M.comoensisIvoryCoast)

dd. Eye 2.25-2.5 in length of head (adult); less than 50mm in standard

length . . . M./odoriCongo)

bb. 29-33 lateralline scales(body depth 3.5-4.2 in standard length; longitudinal

band complete).

1.16-19 branched anal rays; scales of lateral line not

marked.

m. Caudal peduncIe 1.15-1.4 times longer than deep

. . . M. lualabae(Congobasin)

mm. Caudal peduncIe 1.5-1.75 times longer than deep

M. argyrotaenia(Angola)

The Petersini are thus composed of 6 monotypic genera which are very

well Characrerized

Tricuspidalestes, Petersius, Arnoldichthys, Ladigesia,

Clupeocharax

and

Lepidarchus

and of three polytypic genera, two of which

are quite complicated and perhaps not monophyletic.

1 GENUS MI R LESTES

Micralestes is the lar,gestgenus of the Petersini as well as the most

generalized.All the speciesare of smallsize(maximumlength 100or 110mm

for the type species, Micralesteshumilis ,are moderately elongate, usually

have a longitudinal dark band, and are very similar to each other. According

to Poll, they can be distinguished as follows:

M/era/estes aeut/dens.

Photo by Dr. Herbert R. Axelrod.

t ,

29


17/127

ll. 19-21 h.:r-mchedana1 rays; sca1esof lateral line with

black spot at base (caudal peduncle as deep aslong)

. . .

M. congicus

Congobasin)

aa. Pairof small teeth behind mainmandibulary serieswith 2-4cusps; up to 12cusps

in the broadest teeth (longitudinal band complete; tip of dorsal fin black; 14-16

branched ana1raysand 26-29lateralline sca1es) ...

M. acutidens

fromNigeria

to Angolaand Zambezi

basin; WestMrica?)

(2) GENUS

PHENACOGRAMMUS

This composite genus inc1udes the

Micralestes-like

species with an

incomplete lateral line (however Micralestes elongatus and comoensis some-

t imes have an incomplete lateral line) , plus cer tain forms which probably

come from di1ferent evolutionary groups but are not separable at the

generic leveI, their characters showing some overlap. These were considered

as genera by Poll. It seems convenient to retain a similar division, but at a

lower leveI, as follows:

a. Lateralline complete.

b. 4t or 5t transverse sca1esbetween predorsal line and lateralline

. . . Ph. altus-group (or

subgenus

Brachypetersius

bb. 6t-7t transverse sca1esbetween predorsalline and lateralline

. . . Ph. ansorgii-group(or

subgenus Nannopetersius

aa. Lateral line incomplete (or not quite complete in certain individuaIs) (4t-8t

transverse sca1esbetween predorsalline and lateralline).

c. 15-21 branched anal rays; unpaired fins often filamentous in adult male;

body of moderate depth (2.6-4.3 in standard length)

. . . Ph. interruptus-group

Phenacogrammus typica1)

cc. 22-25 branched anal rays; unpaired fins unrnodified in adult male; body

usual ly deep (body depth 1 .9-2.9 in st andard leng th)

. . . Ph. caudomaculatus-group

(or subgenus

Bathyaethiops,

type speciesgreeni)

The

Phenacogrammus altus-group

The small species of this group (Iargest 100 mm) are rather well

characterized by their deep body and relatively small number of transverse

scaIes(four or five between dorsal finand lateralline), which is unusual (the

number of scale rows theoreticaIly increases with the depth of the body),

as well as by a peculiar spot on the lower part of the caudal pedunc1e,

present in four species out of six (afifth species has a band going onto the

pedunc1e). These species can be identified as follows:

30

~]

,

,I

'

.

I

fI

11.,

i~

,...

;~'U~-

I

J

-

-

Phenacogrammus a/tus,

juvenlle. Photo by Dr. Herbert R. Axelrod.

a. 5 scales be tween dorsa l fin and la te ra l l ine.

b. A peduncular spot; 16-18 branched anal rays (28-30 lateralline sca1es)

. . . Ph. notospilus(Ogooue,

Gaboon)

bb. No peduncular spot but a broad, diffuse longitudinal band present

. . . Ph. huloti(Congobasin)

aa. 4 sca1esbetween dorsal fin and lateral line.

c. A peduncular spot; 20-27 branched ana1rays.

d. 20-26 lateralline sca1esin a complete series; body very deep, 2.1-2.5 in

standard length (adult).

e. Peduncular spot round . . .

Ph. altus,

synonym

nummifer (Congo basin)

ee . Peduncu lar spo t hor izonta ll y elonga te

. . .

Ph.pseudonummifer

upper

Congo basin)

dd. 25-30 lateral line scales, the lateral line usual ly lacking one or two pores;

body not very deep, 2.4-2.8 in s tandard length (adul t) (peduncular spo t

horiz~ntally elongate)

. . .

Ph.cadwala~ri

(upper

Congo)

cc. No peduncular spot; 18-19branched anal rays (a prominent humeral spot;

speciessomewhat intermediary between this and the followinggroup)

. . .

Ph.gabonensis Gaboon

The

Phenacogrammus ansorgii-group

Ph. ansorgii

and

Ph. lamberti

are small (75 mm) species inhabiting the

coastal part of Gaboon, Congo and Angola. Ph. ansorgii,best known under

the name

Petersiusubalo

(which was named for the female of

ansorgii ,

is

an elegant fish with strong sexual dimorphism, the males having a con-

31


18/127

li. 19-21 Lranched anal rays; scales of lateral line with

b lack spo t a t base (caudal peduncle as deep as long)

. . . M. congicus (Congo basin)

aa. Pair of small teeth behind main mandibu1ary series with 2-4 cusps; up to 12cusps

in the broadest teeth ( longi tudinal band complete ; ti p of dorsa l f in black; 14-16

branched anal rays and 26-29laterall ine scales) ' M. acutidens (from Nigeria

to Angola and Zambezi

basin; West Arrica?)

(2) GENUS

PHENACOGRAMMUS

This composite genus includes the Micralestes-like species with an

incomplete lateral line (however Micralestes elongatus and comoensis some-

t imes have an incomplete lateral line) , plus cer tain forms which probably

come from different evolutionary groups but are not separable at the

generic leveI, their characters showing some overIap. These were considered

as genera by PoU. It seems convenien t to retain a simi lar divi sion , but at a

lower leveI, as follows:

a. Lateralline complete.

b. 4t or 5t transverse scalesbetween predorsal line and lateralline

. . . Ph. altus-group (or

subgenus

Brachypetersius

bb. 6t-7t transverse scalesbetween predorsalline and lateralline

. . . Ph. ansorgii-group(or

subgenus

N annopetersius

33. Lateral line incomplete (or not quite complete in certain individuaIs) (4t-8t

transverse scales between predorsal line and lateral line).

c. 15-21 branched anal rays; unpaired fins often filamentous in adult male;

body of moderate depth (2.6-4.3 in standard length)

. . . Ph. interruptus-group

Phenacogrammus typical)

cc. 22-25 branched anal rays; unpaired fins unmodified in adult male; body

usually deep (body dep th 1 .9 -2.9 in st andard length)

. . . Ph. caudomaculatus-group

(or subgenus

Bathyaethiops,

type species

greeni

The

Phenacogrammus

altus-group

The small species of this group (largest 100 mm) are rather well

characterized by their deep body and relatively small number of transverse

sca1es(four or five between dorsal finand lateralline), which is unusuaI (the

number of scaIe rows theoretically increases with the depth of the body),

as well as by a peculiar spot on the lower part of the caudal peduncle,

present in four species out of six (afifth species has a band going onto the

peduncle). These species can be identified as follows:

30

iJ

~

'~1\.'-W~

--

~-

J

Phenacogrammus altus, juvenile. Photo by Dr. Herbert R. Axelrod.

a.

5 sca les between dorsa l f in and la te ra l l ine .

b. A peduncular spot; 16-18branched anal rays (28-30lateralline scales)

. . .

Ph. notospilus

(Ogooue,

Gaboon)

bb. No peduncu1arspot but a broad, diffuselongitudinal band present

. . .

Ph. huloti

(Congobasin)

33.4 scalesbetween dorsal fin and lateralline.

c. A peduncular spot; 20-27 branched anal rays.

d. 20-26 lateralline scalesin a complete series; body very deep, 2.1-2.5 in

standard length (adult).

e. Peduncular spot round . . . Ph. altus,synonym

nummifer

(Congo basin)

ee. Peduncular spot horizontally elongate

. . .

Ph.pseudonummifer

upper

Congo basin)

dd. 25-30 lateral line scales, the lateral line usual ly lacking one or two pores;

body no t very deep , 2.4-2.8 in st andard leng th (adu lt ) (peduncular spot

horiz~ntally elongate)

. . .

Ph.cadwala~ri

(upper

Congo)

ec. No peduncular spot ; 18 -19 branched anal rays (a prominent humeral spot ;

species somewhat intermediary between this and the fol lowing group)

. . . Ph. gabonensis (Gaboon)

The

Phenacogrammus ansorgii-group

Ph. ansorgii

and

Ph. lamberti

are small (75 mm) species inhabiting the

coastal part of Gaboon, Congo and Angola.

Ph. ansorgii,

best known under

the name Petersiusubalo (which was named for the female of ansorgii ,is

an elegant fish with strong sexual dimorphism, the males having a con-

31


19/127

Type of Phenacogrammus ansorgll after Poli , 1967 .

spicuous humeral spot and a rather pale, diffuse lateral band up to the tip

of the middle caudal rays, as welIas filamentous fins, whereas the female

has only the longitudinal color pattem. Ph. lamberti has the same fila-

mentous fins in the males chiefly the dorsal fin and a much more con-

spicuous lateral band from snout to tip of middle caudal rays , as welIas

a characteristic blackmark spot or band on each caudallobe. Apart from

the coloration, the two species differ in the number of lower gill-rakers,

10-12 in lambertiagainst 14-17 in ansorgii.

h

Phenacogrammus interruptus group

This group is mostlyknown to aquarists by the type species of the genus,

the Congo tetra, Phenacogrammusinterruptus which has a particularly

brilliant coloration. Other species, such as Ph. major Ph. urotaeniaand Ph.

aurantiacus

would be equalIy suitable for the aquarium. One species from

the Congo, Ph. polli is very different from alI other species, having up to

35 or 37 longtudinal scalesand 6 or 7 scalesfrom dorsal fin to lateralline.

It is very smalI 32 mm with a more or less diffuse lateral bando

A second species,

Ph pabrensis

from the upper Volta, is also quite dif-

ferent in having a peculiar modificationof the anterior lobe of the anal fin

in the adult male; the fiest rays are thickened and curved, the concavity

toward the fore-part. This sexual dimorphism is also to be seen in

Micralestes elongatus M. brevianalis

a synonym of the West Arrican

populations of Micralestesgcutidens? and in Hemigrammopetersiusinter-

medius.

In other Petersini, mature males have the anterior lobe of the anal

fin thickened, but the rays have their concavity toward the back. This is

why a new genus, Virilia had been proposed for P. pabrensis.This genus

is not retained here.

32

Hepsetus odoe

Photo by Pierre Brichard.

Hepsetus odoe Larger individual with spotted fins. Photo by Hllmar

Hansen, Aquarium Berlln.

33


20/127

t

'~ .

~ '

1

~

.

'':~

t r

Phenacogrammus nterruptus

Photo by G. Tlmmerman.

Another group indudes a dubious species Ph. stigmaturafromCameroon)

and 5 very dose forms. Ph. stigmaturahasfew longitudinal scales(about 20)

and differs from Ph. interruptusin the presence ofan unusual small spot at

the base of the lower caudal lobe.

The last 5 species, which measure about 80mm in standard length, have

in common their sexual dimorphism, males of most of them having fila-

mentous dorsal and caudal fins, a deeper body and a more brilliant colora-

tion than the females, and many overlapping meristic characters. They falI

nevertheless into twogroups, depending upon color pattern: Ph. interruptus

and aurantiacuson the one hand, have a diffuse,often not very conspicuous,

broad lateral band; Ph. major,Ph. urotaeniaand Ph. deheynion the other

band, have a black band (after preservation) from the level of the dorsal

fin, or farther back, to the end ofthe caudal rays, this band extending onto

the lower part of the caudal pedunde only.

Ph. interruptus, from the Congo basin (called the Congo tetra by

aquarists) differs from

Ph. aurantiacus,

also from the Congo basin (and

Gaboon), mostly in the color of their fins, which are mostly pink to purple

in Ph. interruptusand orange (ventral and anal fins) to carmine red (base of

pectoraland dorsal fins andwholeadiposeand caudalfins)in Ph. aurantiacus.

Both have a body shining with alI the colors of a rainbow. Museum

specimens can be told apart by the number of scales(20-23in a longitudinal

series, versus 23-26respectively) and chiefly by the inner mandibular teeth

which are very small or even lacking in 20 of the specimens of Ph.

34

aurantiacus.

The latter species is evidently at the limits of the genus

Hemigrammopetersius

where those teeth are alwayslacking).

The other three forms, Ph major, Ph. urotaeniaand Ph. deheyni, could

very well be lumped in the future into a single polytypic species. They

usually have a conspicuous humeral spot and the characteristic peduncle

p~ttern described above. The coloration of only Ph. urotaeniais known

with precision. In males the flanksare purple and the belly, the eye and alI

the finsare light carmine. The females are lesscolorful,more elongate, and

they have two dark lines above their anal fino

The Phenacogrammus caudomaculatus-group

The three Congolese species of the Ph. caudomaculatus-group,or sub-

genus Bathyaethiops, are deep bodied fishes, as deep as Phenacogrammus

altus, which are rather wellcharacterized by a large ovate black spot which

extends (or almost extends) onto the entire depth of the pre-peduncu1ar

region, i.e. just above the last anal rays. They usually have a rather small

humeral spot and a series of chevron-like stripes along the flanks.

Ph.

caudomaculatus,the Mrican moon-tetra, is by far tlie most common of the

three species. Ph. greeni (type species of Bathyaethiops differs from it in

having more transverse, longitudinal and peduncu1ar scales (7 -St/36-42/

41-5.t, 14-16peduncu1ar, in greeni, versus 5 -7t/28-35/3 -41, 10-12ped.,

in

caudomaculatus .Ph. breuseghemi

has the same meristics as

Ph. caudo-

maculatus, but it is somewhat less deep, with the peduncu1ar spot more

posterior and only on the lower parto

Phenacogrammuscaudomaculatus

(after Poli, 1959).

35


21/127

Brycinus macrolepidotus

juvenile. Photo by Dr. Herbert R.

Axelrod.

Bryconaethiops

sp. apparently not

B boulengeri

or

B micro

stoma


Brycinus imberi

from Chete Island cove Lake Kariba. Photo by Dr. E.

Balon.

r

I

Brycinus macrolepidotus

adult from Gaboon. Photo by Dr. J.

Gery.

~


22/127

d. Broadest premaxillary teeth usual1ywith less than 9 cusps

. . .

H. caudalis-group

( genus

A estopetersius,

rype species

hi gendorfi)

dd. Broadest premaxil lary teeth usual1y with 9-14 cusps

. . .

H. tumbensis-group

(for

which PolI has proposed

the genus

Duboisia estes)

bb. Lateralline incomplete (except sometimes in H. intermedius); species from the

Cameroon and Tchad . . . H.pulcher-group

Hemigrammopetersius in t he

strict sense)

aa. Preventral region keeled; mouth superior; dorsal fin far behind mid-body

(otherwise very similar to

Hemigrammopetersius intermedius)

. . .

H. barnardi

(East Afric-

probably a new generic

rype)

rcuspdalestes caeruleus (after Poli, 1967).

3 GENUS TRICUSPIDALESTES

The single Congolesespecies, T. caeruleus,has the narrowest teeth of all

Petersini (except

Clupeocharax

and

Lepidarchus).

It is a smallfish (44mm)

having the form ofa

Micralestes

but with long finfilaments,a large eye and

a large,maxillary bone, somewhat clupeoid in appearance. Its scales are

numerous (36-41 in a longitudinal series, 3-6 of which are perforated, and

7 or 8 from dorsal fin .to lateralline). The overall coloration is steel-blue,

with the head and fins dark, and the backand flanksdeep blue or mauve.

It would certainly be a prized aquarium fish.

The Hemigrammopetersius tangensis-group

The H. tangensis-group(sometimes called Rhabdalestes)inc1udes6 or 7

small (maximum 75~) species mostly from East and South Mrica

H. tangensis, H. maunensis, H. rhodesiensis and H. leleupi), with a few forms

from West Africa H. septentrionalis, H. loennbergi and H. eburneensis). They

are usually elongate and resemble certain Micralestes, from which they differ

only, or mainly, in the absence of the pair of small teeth behind the main

mandibulary series.

The East and South Afr ican forms may be distinguished as fol lows:

a. 28-29longitudinal scales, 10around caudal peduncle (lateralline complete)

. . . H. maunensis

(Bechuanaland)

aa. 35-37 longitudinal scales, 12-14around caudal peduncle.

b. Lateralline complete.

c. An inconspicuous dark line on caudal peduncle

. . . H. tangensis (East Africa)

cc. Lateral band conspicuous, mosdy posterior; anal finbase with a black band

. . .

H. rhodesiensis

Rhodesia)

bb. Lateralline incomplete, without pores on caudal peduncle; colorationsame as

rhodesiensis . . . H. e eupiEastAfrica,

probably an isolatedform

derived fromH. tangensis)

4 GENUS H MIGR MMOP T RSIUS

Like Phenacogrammus, Hemigrammopetersius has been split into four

subgroups which have generic status according to Poll. However, the

characters alleged for the division show considerable overlap and the

genera cannot be retained here. This overlap (with the exception of a

specialized form,

H. barnardi)

is clearly apparent in the following key:

a. Preventral regionnot keeled; mouth terminal or not much superior; dorsal finnot

much behind mid-body.

b. Lateral line complete or not quite complete, rarely incomplete.

c. Elongate specieswithout filamentson the fins, derived from Miera estes,with

usual1y more than 2 outer premaxillary teeth on each side; 2 subgroups,

East Africanand WestAfrican . . . H.tangensis-groupgenus

Rhabda estes)

cc. Deeper bodied species with filamentous fins on the males, resembling

Phenaeogrammusand perhaps derived from it, with 2 outer premaxillary

teeth; al1species Congolese except one from Nigeria.

The West African forms are even closer; all have 14-17 branched anal

rays, and the numbers of scalesand gill-rakers overlap. They alsohave in

c0 llmon a black longitudinal band, more conspicuous posteriorly, and a

blackanal fin margin. The only differential characters are as follows:

38

39


23/127

i

I

~ .~

-~

,

'\

~

Brycinus chaperi. Adult male. Photo by Or. Herbert R. Axelrod.

Male (above) and female (below) Brycinus lateralis from Chikanka

Island cove, Lake Kariba. Photo by Or. E. Balon.

~

~ 't'lf

~ ;.JoA (j

.4 y

~

~/

....

',,

'~

,

-

J

)'

f

-

/'

Young rycinus chaperi from Lagos. Photo by Or. Herbert R xelrod

rycinus longipinnis

male

above

and female

below. Photo by J. Elias.


24/127

a.Tip of dorsalfin black.

b. Lateralline complete,with 22-26tubes sometimeswith a pair of conica1teeth

behind the main mandibu1aryseries; a connecting link withMicralestes ?

. . .

H. eburneensis

endemicin

the Cavallyin Ivory Coast

bb. Lateralline perforating only17-24sca1es . . . H. loennbergiGambia,

Comoein Ivory Coast,and

BlackVolta

aa. Tip of dorsal fin hya1ine . . . H.septentrionalisfrom

Senegal to Cameroon

One of the types of

Hem grammopeters us tangens s

after Poli

1967 .

h

Hemigrammopetersius caudalis-group

The seven species of the H. caudalis-group constitute a rather homo-

geneous group, with the exception of H. hilgendorfi type of the genus

Alestopetersius which is quite aberrant in having 34-42 lateral line scales

instead of 27-33 for the bulk of the group and up to 8 scalesbetWeenthe

dorsal fin and lateralline. Six of the seven species are Congolese and the

males of 6 out of 7 species have a filamentous dorsal fin, while 2 have the

middle caudal rays prolonged as in certain speciesof Phenacogrammus.

The species are relatively easyto identify, as shown in the followingkey.

The commonest speciesare H. hilgendorfiand H. caudalis which is some-

times found in the aquarium trade under the name Petersiusxenurus.

42

I

Key to the species of the

H. caudalis-group:

a. 27-33longitudinal scales plus 1or 2 on caudalfin ; 5-7transverse scalesbetween

dorsal fin and lateralline.

b. 13-20 gill-rakers on lower part of first arch.

c. Fins hyaline.

d. No broad lateral band from eye to end of middle caudal rays often a

lateral streak which may get broader on caudal peduncle .

e. Caudal fin of males without prolonged median rays.

f. Body depth 3.0-3.15 in standard length; 27 + 2 longitudinal scales;

16 gill-rakers; a conspicuous triangular caudal spot; humeral spot

scarcelyvisible

. . . H.smykalaiLowerNiger

ff. Body depth 2.4-3.0 in standard length; 30-33 + 1 or 2 longitudinal

sca1es;13-14gill-rakers; no caudal spot; humeral spot large, vertica1ly

elongate

. . . H.compressusCongo

ee. Caudal fin of males prolonged body depth 2.5-2.8 in standard length;

27-32 + 1 or 2 longitudinal scales; 13-18 gill-rakers; humeral spot

verticallyelongate;a blacklateralline extendingonto caudalrays, where

it ismuch broader . . . H.caudalisynonym

H. xenurus

Congo

dd. A broad lateral band, equallybroad from eye.to end of prolonged middle

caudal rays body depth 3.25-4.0 in standard length

. . . H. brichardi Congo

Hem grammopeters us caudalis Photo by Milan Chvojka.

43


25/127

Mcralestes storms Photo by Or. Herbert R. Axelrod.

Mcralestes acutdens from Northern Rhodesia. Photo by Or.

Herbert R. Axelrod.

44

..........--

Young Phenacogrammus nterruptus Photo by Or. Herbert R. Axel-

rodo

Male Phenacogrammus nterruptus the Congo tetra. Photo by. Or.

Herbert R. Axelrod.

..

~ - - -~

~~. ~

.~

.~ ~

~

~

~~

45


26/127

cc. Fins black, particularly the filamentous dorsalfin and the caudalfin except

at its base) middle caudalrays not prolonged; a humeral spot; body depth

2.9-3.4 in standard length; a sibling species of

H. hilgendorfi

?)

. . .

H. nigropterus

Congo)

bb. 24-29 gill-rakers on lower part of mst arch dorsal and caudalfins not pro-

longed; a broad lateral band from eye to end of middle caudal rays; dorsal,

pectoral and ventral fins black) . . . H.leopoldianusCongo)

aa. 34-42longitudinal scales plus 1or 2 on caudlfin); 7-8transverse scalesbetween

dorsal fin and lateralline dorsal fin filamentous, middle caudal rays not pro-

longed; a vertica1lyelongate humeral spot; fins black in adult male)

. . H. hilgendorfi Congo)

h

Hemigrammopetersius tumbensis-group

T his g ro up , f or which P oU p ro po sed a ne w g ene ric na me

Duboisialestes

owin g to its e xtremely br oa d tee th 6 to 14 c us ps ins te ad o fus ua lly les s than

9 cusps for the

H. caudalis-group ,

is c ompos ed of on ly 2 s pe cies ,

H. tum-

bensis

from the Stanley Pool Lower Congo), known as

H. duboisi

by

aq uar is ts , an d a muc h r ar er sp ec ie s,

H. bifasciatus,

f ro m the Midd le Co ngo

ba sin. Th e latte r ha s mor e s cales 7t/3 4- 36/3t, 1 3- 15 p ed. , in

H. bifasciatus,

v er su s 5t-6t/30 -3 3/3t, 1 0- 12 p ed ., in H. tumbensis and conspicuous black

marks on the base of the caudal lobes.

H. tumbensis

resembles

H. caudalis,

with which it has been confused having been descri bed as a subspecies of

H. xenurus

which is a synonym of

caudalis .

Anal fln of a female above) and male Hemigrammopeterslus inter-

medlus after Gery, 1968).

46

.I-

Hemigrammopetersius pulcher, type after Poli, 1967) and H. tumben-

sis, typ e after Poli, 19 67 ).

h Hemigrammopetersius pulcher-group

One species surely belongs here, the poor1y-known

H. pulcher

ftom the

Ia River in Ca meroon, bec ause it is the type of the ge nus Hemigrammo-

petersius.Only two specimens are known, which look similar to the Phena-

cogrammusmajor-urotaenia-deheynicomplex, but without the pair of small

conicalteeth behind the main mandibulary series.

Three additional species are provisionally referred to the group by PoU,

H. brevidorsalisand H. intermediusfrom the Tchad and Chari Riv er, and

H. barnardifrom East Africa.The first two species are said to differ mostly

in the number of gill-rakers. However,

H. brevidorsalis

is known on1yfrom

damaged adult specimens and some juveniles. Males of H. intermediusare

rather similarto those of

H. septentrionalis,

and certain specimenseven have

the latera1linecomplete or almostcomplete. They have a thickened, rounded

anal fin, surrounded by a broad black bando

H. barnardiis different from aUother speciesof the group, being adapted

to a lifenear the surface. It may be a new generic type, but for the moment

is retained

in emigrammopetersius


27/127

hen cogr mmus

aurantiacus A male individual without very much

color in its fins Photo by Dr Herbert R Axelrod

Male henacogrammus urotaenia Photo by Dr J Gery

henacogrammus ansorgii Photo by Dr Herbert R Axelrod

henacogrammus huloti Photo by Pierre Brichard

:;.. .

;

8

9


28/127

(5) GENUS PETERSIUS

The single species Petersius conserialis from around Dar-es-Salaam in

Tanganyika (coast of East Mrica), is quite unusuaI among this group of

genera in attaining a relatively large size (145mm), the mouth uptumed

with the mandible prominent, and in Iackinga posterior fontaneI. It has a

caudal spot extending onto the middIe caudal rays. This is about alI that is

known of this species.

(6) GENUS ARNOLDICHTHYS

The single(?) speciesArnoldichthysspilopterusthe Niger tetra orArnold s

characin, is well known to aquarists. It is unusual not only in having dif-

ferent sizesof scales,but also in havinga larger number of teeth than other

Petersini. The role of 4 inner premaxillary teeth, for example, which

has few exceptions, isnot valid here. The Niger tetra has up to 7 inner teeth

on a side. The sameis ttue for the lower rowof teeth and, in fact, lacking

the pair of conical teeth on the mandible, this Mrican tetra has almost the

same dentition as that of its American cousins. However, the shape of its

body, and chiefly of its snout, is distinctly alestid, indeed, much more

Brycinus like

than

Micralestes like.

Its rainbow coloration is well known and need not be described here.

The sexual dimorphism of its anal fin is lesswellknown. In the female, the

anal fin, with the border almost straight like that of other alestins, has a

black spot in the Iast rays; in the male the analfin, with a convex edge, is

tricolor, red and yellowwith a black border. According to certain aquarists,

there is a polymorphism in this color pattem, somemales (or males of a

sibling species?) having an irregularly striated anaI fino

Petersius conserlalis and Clupeocharax schoutedenl (aftar Poli, 1967).

(7) GENUS LADIGESIA

A singlespeciesfrom Sierra Leone, hasrecent1ybeen described, Ladigesia

roloffi

but slight1ydifferent forms have been collected since in other parts

of West Mrica.

The jelly bean tetra is another peculiarityof the Mrican tetras. It has a

good part of the predorsal region entirely naked, and its upper teeth point

outward. Its body shape and black color pattem resemble that of an

ordinary Hemigrammopetersiussuch as H: septentrionalisor H. inter

medius

but the adult males (largest size 35-40mm) are entirely bright

vermilion.

retained the body shapeof a Petersini, but hasacquired a clupeoid,uptumed

mouth with a blade-like maxillary in a remarkable convergency with some

Aphyoditeini (American), Brittanichthys for example. This smaIl fish

(47mm) is a speciesfrom the region ofLake Tumba (near the confluenceof

the Ubanghi with the Congo), where it performs seasonal migrations,

according to Matthes, as well as from another lake of the central Congo. It

is a pelagic plankton-eater and, as such, is not very colorful, being without

marks except for a narrow lateral line.

8 GENUS

CLUPEOCHARAX (synonym CLUPEOPETERSIUSj

The single species Clupeocharaxschoutedeni (do not confuse it with

Clupeacharax which is a South American genus) is again aberrant: it has

(9) GENUS LEPIDARCHUS

The single species Lepidarchusadonis if .one of the most striking dis-

coveries of recent years. This minute (less than 20mm standard length)

West Mrican fishis entirely devoid of scaIesand lateralline. The teeth, like

those of

Clupeocharax

are in a single series on both jaws, min~te, conicaI,

but the maxillary is not clupeoid.

The male has numerous purple spots onthe distal haIfof its body aswell

as on the caudal finoThe ventral and anal fins are likewisespotted or even

barred, whereas the front part of the dorsal fin isbrown in both sexes.

50

51


29/127

~ ~

1

...

Hemigrammopetersius caudalis the yellow-tailed Congo tetra.


Hemigrammopetersius intermedius Photo by H.J. Franke.

----

Phenacogrammus caudomaculatus the African moon-tetra.


Hemigrammopetersius rhodesiensis Photo by Warren

E Bur

gesso

52

53


30/127

SU F MILY HYDROCYNIN E

frican TigerFishes

Hydrocynus not Hydrocyonas it is frequently spelled) species are A/estes

modified toward predation. They have acquired strong, acute, uniserial

canine teeth, those ofthe upper jaw altemating with those ofthe lower and

acting as a trapo This makes the tiger fishes some of the most formidable

fish-killers of African waters.

Six species are known, difi eringin the number of scalesand in certain

proportions. H. forskalii and H. vittatus, very dose species, are widely

distributed in Mrica. They are found from the Nile, Senegal and Niger

to the Congo, with H. Ottatuseven extending to South Mrica. H. brevis

and

H. somonorum,

siblings in Niger and Tchad, are restricted to West

Mrica, whereas H. vittiger and the giant tiger fish, H. goliath, inhabit the

Congo.Most of the species reach 40or 50em, or even 68cm for H. brevis.

The record sizeis held byH. goliath,which attains a length of 132em and

a weightof 38kg, and which is saidto reach 150em and 50kg on occasion.

Certain species are brilliantly colored during the breedin~ season.

H. vittatus for example, the most ubiquitous, haS a series of longitudinal

lines formed by spots at the baseof each scale,has the eye and ventral fins

red, and has the other fins at least partially orange.

Most of these characters are quite specialized. The three subfamilies

can be told apart by means of the following key:

Key to subfamilies of Citharinidae:

a. Premaxillary bones short and not movable; joint between two sides of mandible

movable.

b. Sca1escyc10id except in one species); body short and compressed, bream-like

. . . CITHARININAE

bb. Scales always ctenoid; body short and compressed only in a few instances

(XenocharaxandDistichodus)

...

DISTICHODINAE

aa. Premaxillary bones long and movable; joint between two sides of mandible not

movable

. . . ICHTHYBORINAE

Family Citharinidae

Citharinids

SU F MILY CITH RININ E

itharins

This smalI group of large, usually deep-bodied, limnivorous species is

exactly homologous to the American prochilodins and, like the latter, are

of economic importance in certain regions of tropical Mrica. The largest

speciesreaches a sizeof 80em and a weight of 18kg. The scalesare cydoid

in

Citharinus

and ctenoid in

Citharidium,

and are numerous 46to 90in the

lateralline, which is complete). The dorsal and anal fins are relatively long

16-24 rays for the former and 19-31for the latter) in relation to the great

depth of the body. The mouth structures are well adapted for feeding on

the mud at the bottom of rivers: it isverybroad, with veryweakteeth inser-

ted into the lips; the maxilIary bones are not toothed; the gill-rakers are

numerous; and the intestinal tract is very longo

The citharinids, strictly Mrican, are sometimes split into 2 families

Distichodidae and Citharinidae) or even 3 with the Ichthyboridae). These

groups will be treated here as subfamilies which have the following

characters in common:

-Scales ctenoid with the exception of the genus Citharinus).

-Ventral rays usualIymore numerous than in the other characoids except

hemiodids).

-Only two epurals.

- Teeth small, often movable, usually cuspidate again a convergence

with the hemiodids).

-Presence of pharyngea1 bags .

-According to Daget, interca1arium very small and incorporated into

the neurocranium whereas in a non-citharinid such as Brycon, it is a

separate small osseous plate covering the prootic and other bones of

the cranium).

-Joint betweenthe two sides ofthe mandible simple, without interIock-

ing devices, often ankylosed.

GENUS CITHARINUS

Seven species belonging to the genus Citharinus which is split by some

into three subgenera) are known. The folIowing key wilI help in the identi-

f icat ion of these species af te r J . Daget):

a. Relativelygeneralized forms with body not very deep and adipose fin base not

very long shorter than its distance to the dorsal fin).

b. 7 or 8 transverse sca1erows between lateralline and ventral fin; 46-51 lateral

line sca1es;body depth 2.2-2.7 in standard length

. . . C. distichodoidesTchad and

Niger basin)

bb. 10-20 transverse sca le rows between lateral l ine and ventral f in; 55-90

lateral line scales; body depth usually less than 2.3 in standard length.

c. 10-12transverse scalerows between lateralline and ventral fin; 55-60 lateral

line scales . .. C.macrolepisCongoasin)

cc.More than 12transversescalerows;more than60 lateralline sca1es.

d. 13or 14transversescalerowsbetweenlateralline andventralfino

e. 60-661aterallinecales . . . C.congicusCongobasin)

ee. 68-73lateralline scales . . . C.eburneensisIvoryCoast)

; ~

td~/IJ Mele

Rap1 PII.

Da,det

C. po.,. ~,:j- ,\ I ,\

89.000-

M.na..

- AmazoA a~

55

4


31/127

...............

I

,

I

f

/

Unidentl fied Afr lcan tetra. Photo by Klaus Paysan.

I

..

.

\

\\

rnoldichthys spilopterus tlTe Niger tetra. Photo by Dr. Herbert R.

Axelrod.

Ladigesia roloffi the jelly bean tetr a. Phot o by E. Roloff.

-

Lepidarchus adonis Photo by E. Roloff .

.-...

56

57


32/127

dd. 17-20 transverse scale rows between lateralline and ventral fin 77-90

lateralline sca1es . . . C.citharus,ypespeciesf

the genus

Citharinus

from

Senegalto Nile basin

aa. Specialized,deep-bodied forms with an elongate adipose finbase longer than its

distance from dorsal fin .

f. 10-12 transverse scale rows between lateral line and ventral fin;

53-60lateralline sca1es same sca1ationas that or C. macrolepis

. . . C.

gibbosus

Congobasin

ff. 13-15transversesca1erows between lateralline and ventral fin; 59-71

laterallinescales . . . C. latusfromSenegalo

Nilebasins

GENUS ITH RIDIUM

The second genus,

Citharidium,

with the singlespecies

ansorgii,

from the

Niger basin, is exactly like the deep-bodied Citharinuswith a long adipose

fin, but its scales 46-50 in lateralline and 11or 12between lateralline and

ventral fin bear longitudinal along axisofbody , parallel ridges terminating

in spines. According to Daget, these sca1esare different from the typical

ctenoid scales of the next subfamily.

SU F MILY DISTICHODIN E

Distichodins

The Distichodinae is a relatively large group of about 50 or 55 micro-

predator and herbivorous species. They are distr ibuted among fewer than

10 genera, as follows:

a. Generalized forms with gill membranes not rormmg a continuous bridge under

throat; body deep, head broad and snout obtUse two or three rows of teeth on

both jaws . . . 1 Xenocharax

aa. More specialized forms with gill membranes forming a continuous bridge under

throat; body shape variable two series of teeth on both jaws .

b. Gill membrane not fused with throat or isthmus; maxillaryteeth often present

smallrather elongatespecieswith head narrowand snout more or less pointed .

c. 31-48 lateralline or longitudinal scales.

d. Lateralline complete; adipose fin present

2 Nannaethiops

dd. Lateral line incomplete; adipose fin present or absent.

e. 10-14 dorsal fin rays; maxillaryteeth present

.

. . 3

Neolebias

ee. 15-16 dorsal fin rays; maxillary teeth present or absent.

f. A series of pit-lines on head; maxilla toothless; adipose finpresent

. . .

4 Congocharax

fr. No pit-lines on head ? ; maxilla toothed; adipose fin absent

. . . 5 Dundocharax

cc. 59-73 lateral line sca1es; a genus forming the transition with the

Ichthyborinae

. . .

6

Microstomatichthyoborus

58

.,......--

PIxxxn

f,

....

i;,or

Type of Citharinus gibbosus after Boulenger, 1899 and type of Cltha

r d um ansorgii after Boulenger, 1909 .

59

--


33/127

ydro ynus

sp possibly H. goliath or may bea giant specimen of H.

vttatus. Photo by Dr J P Gosse

60

. . ..- -- -

~ji . fJ -

:7

~\.

, , ~ iL ,.

.

v

,,, .,.,

( ~

. . . I I

,/ .1 1.; . - -:; ,

. , r

. . . ,>~,. .. . ... ~(

~

~

~...

..

>i..-

.,., .:-

1. .

1

, J.

Hydrocynus vttatus juveniles trom Lake Karlba Photo by Dr E

Balon

Ctharnus ctharus. Photo by Klaus Paysan


34/127

bb. Gill membrane fused with isthmus; maxillatoothless.

g. Two series of bifid teeth on both jaws; dorsalfin long, with 16-27

rays.

h. Large deep bodied species, quite comparable to the Citharl-

ninae; adipose and caudal fins sca1ed

. . .

7) Distic1wdus

hh. Small,elongatespecies;adiposefin not sca1ed

...

S Paraduc1wdus

gg. A single series of teeth on both jaws; dorsal fin relatively short,

with 12-16 rays.

i. Lateralline complete

i i. Latera1line incomplete

. . .

9) Nannccharax

. . .

10) Hemigrammocharax

relatively large size: 62 mm) . . . genus

Nannaethiops

a

single species,

N.

unitaeniatus,from Niger to

the Congo basin)

aa. Lateral l ine incomplete adipose fin present or absent; inner teeth bifid or

conicalon both jaws; 2-7 maxil lary teeth) . . . genus

Neolebias

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