The characiform fishes of the Apure River drainage, Venezuela

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Title:
The characiform fishes of the Apure River drainage, Venezuela
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2 v. (vi, 892 leaves) : ill. ; 29 cm.
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English
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Taphorn, Donald C., 1951-
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Characiformes   ( lcsh )
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bibliography   ( marcgt )
theses   ( marcgt )
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Thesis:
Thesis (Ph. D.)--University of Florida, 1990.
Bibliography:
Includes bibliographical references (leaves 864-886).
Statement of Responsibility:
by Donald C. Taphorn.
General Note:
Typescript.
General Note:
Vita.

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University of Florida
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Full Text











THE CHARACIFORM FISHES
OF THE APURE RIVER DRAINAGE, VENEZUELA

















By

DONALD C. TAPHORN


A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA


1990












ACKNOWLEDGMENTS


Saying thank you is hardly adequate to repay the many people who have

helped me in this project. They have given me tremendous gifts: precious

time, sound advice and useful suggestions, as well as moral and financial

support and many other things. They helped get the fish out of the water

and into a jar in the museum, get the sometimes jumbled ideas in my head

into some semblance of order, get my body out of bed and into the lab, and

get the words out of the computer and onto this page. But thank them I

must and I do so sincerely.

My parents and family are first in this list of special people who

have helped. They are always with me in spite of the large distances that

have separated us. Next I thank the many friends, professors, colleagues

and students who have helped to make this dissertation possible. They are

Dr. Carter Gilbert, cochairman of my committee for these many years and

tireless in the dreary task of wading through and correcting the rough

drafts, Drs. Horst Schwassmann, Frank Nordlie, and Nigel Smith, who pa-

tiently served on my committee and suggested many helpful improvements and

Dr. Craig Lilyestrom, his wife Maria and their children Lynda and Wayne who

shared a home with me in Venezuela. During my visits to Gainesville, I

enjoyed the warm hospitality of Dr. and Mrs. Carter Gilbert, Mr. and Mrs.

George Burgess, and Mr. and Mrs. Terry Converse.

Dr. Kirk Winemiller, Mr. Leo Nico and Mr. Stewart Reid worked on

postgraduate degrees in our laboratory, shared in the field work, and






generously provided specimens and information on the ecology of Apure drain-

age fishes from their master's and doctoral work.

I also thank the friends and colleagues who helped pull the other

(usually the deep) end of the seine, Craig Lilyestrom, Craig and Carmen

Olds, Leo Nico, Stewart Reid, Kirk Winemiller, Oscar Leon M., Naboth

Montilla A., Mike Taphorn, Pablo Osman, Larry Page, Carter Gilbert,

Richard Franz, Jack Karr, Jamie Thomerson, Guillermo and Ram6n Feo,

Alex Flecker and many others too numerous to mention here. Special

thanks go to Ing. RNR Angelina Licata and Mr. Oscar Leon Mata for the

drawings and to Lic. Jairo Perez and Ing. Aniello Barbarino D. for the

maps. Three technicians have worked with me in the Fish Collection,

Aldo Garcia, Eric Sutton and Keyla Marchetto; I am greatly indebted to

them for their assistance with the unending museum chores of processing

and cataloging the specimens, preparing labels and card files, and

keeping the computer records up to date. Several of my students in the

Environmental Engineering Department have done thesis work on fishes,

and many also held student jobs in the Fish Collection and helped with

the museum chores. Special thanks go to Pablo Osman, Norberto Saavedra,

Enrique Marzola, Aniello Barbarino Duque, Cecelia G6mez, Guillermo

Cedefo, Ricardo Smith, Yury HernAndez. I also thank Dr. Richard Schar-

gel for his helpful talks about Apure drainage soils and Prof. Heberto

Pacheco and the other personnel of the Cartographic Center of UNELLEZ

who helped obtain topographical maps.

The Secretario de Investigaci6n de la UNELLEZ, FONAIAP, FUNDA-

CITE, CONICIT all provided financial support for this project.












TABLE OF CONTENTS


page


ACKNOWLEDGMENTS.............


........ i i


ABSTRACT..............................................
INTRODUCTION.....................................


MATERIALS AND METHODS.......
Collecting...............
Curation.................
Material Examined........
Format...................
RESULTS.................
Characiformes...........
Anostomidae.............
Characidae ..............


Characidiidae ....................


Chilodontidae.....
Ctenoluciidae.....
Curimatidae.......
Cynodontidae......
Erythrinidae......
Gasteropelecidae..
Hemiodontidae.....
Lebiasinidae......
Parodontidae......
Prochilodontidae..


DISCUSSION..........................................
Ecological Considerations .......... ...............
Zoogeographical Considerations....................


21
23
31
100
606
664
670
677
721
739
760
766
777
796
808

823
823
854


LITERATURE CITED..................................... 864

APPENDIX.............................................. 887
BIOGRAPHICAL SKETCH.................................. 891


11111


Ilfllll


11111.11


11111.11













Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy

THE CHARACIFORM FISHES
OF THE APURE RIVER DRAINAGE, VENEZUELA

By

DONALD C. TAPHORN

May, 1990

Chairman: Dr. Carter R. Gilbert
Major Department: Zoology

The Apure River drainage of Venezuela collects waters from many

different aquatic habitats that vary greatly in geology, climate, vegeta-

tion and altitude. Over ten years of sampling has yielded 354 species of

freshwater fishes pertaining to ten orders and forty-one families. This

report includes taxonomic synonymies, keys, illustrations, morphological

descriptions, distribution maps, data on abundance, habitat, life history

strategy and diet for 138 Characiform species of the families Anostomidae,

Characidae, Characidiidae, Chilodontidae, Ctenoluciidae, Curimatidae,

Cynodontidae, Erythrinidae, Gasteropelecidae, Hemiodontidae, Lebiasinidae,

Parodontidae, and Prochilodontidae.

Fish distribution within the Apure River drainage is primarily gov-

erned by two parameters, altitude and water chemistry. The few characi-

forms adapted to mountain and piedmont conditions tend to be restricted

in distribution to only those areas.






In the llanos, two assemblages are recognized. Whitewater, muddy

streams are the most common habitat in the drainage, but few characiforms

are restricted only to them. Blackwater habitats with distinct fish assem-

blages exist in isolated pockets in the Aguaro-Guariquito drainage, in the

Caicara Creek drainage of northern Apure state, and in west-central Barinas

state.

The drastic changes in climate between wet and dry season in the

Apure River drainage have molded characiform life history strategies. Most

characiforms have adopted an rl or r2 life history strategy. Of 68 species

that have adopted the rl strategy, most are small omnivorous fishes with

low juvenile and adult survivorship, low fecundity per reproductive bout

(but repeated reproduction throughout the rainy season), short generation

times (many live less than one year), and widely fluctuating population

densities during the year. The other 70 species present have been classi-

fied as r2 strategists. These species typically are larger, are often

migratory, and reproduce annually in a single massive spawning event.

Juvenile survivorship is low, but adults live for several years and reach

larger sizes. Populations fluctuate greatly from wet to dry season because

of the high juvenile mortality. No characiforms in the Apure drainage have

adapted the K-strategy.

The Apure drainage ichthyofauna is a mosaic of relatively young

species that have evolved in the whitewater habitats and blackwater species

probably derived from an older Guyana Shield fish fauna.













INTRODUCTION


Tropical aquatic ecosystems are suffering rapid modification and

deterioration as man's growing population makes ever-increasing demands for

water, forest products, and agricultural land. Many Venezuelan rivers are

already so polluted that we will never know much, if anything, about their

original fish faunas. Fishes are suffering loss of habitat to wetlands

drainage programs, habitat modification by dams and dikes, pollution from

urban sewage, agricultural fertilizers and biocides sedimentation from

deforestation and poor upland watershed management, overfishing, and the

introduction of exotic species.

Efforts to produce effective management plans for a rational develop-

ment of tropical aquatic resources suffer from an almost total lack of basic

information about the aquatic organisms that occupy these systems. Not even

lists of the fishes, mollusks, crustaceans, aquatic insects, plants, etc.,

can be found for most tropical rivers, much less data on abundance, life

histories, critical habitat requirements or other aspects of their biology.

Furthermore, the majority of these organisms have never been sufficiently

sampled, nor has their taxonomy been adequately studied. The literature

provides few guides to the identification, and for the most part, original

species descriptions are hidden in old primary references not usually avail-

able to workers in South America. What little information is available is

seldom written in Spanish, and so is of little use to management officials.

For these and many other reasons, inventories of tropical aquatic organisms






are desperately needed. The decision to undertake a faunal survey of the

Apure River drainage, part of which forms the basis of my doctoral disserta-

tion, is in response to this need.

In South America the Orinoco River Basin (fig. 1) collects the waters

of a vast area covering approximately 1,123,000 km2, second only (although

the Rio La Plata is longer) to the immense Amazon River Basin to the south,

which drains some 7,000,000 km2 (Zinck 1977, Smith 1981). About three-

fourths of the area of the Orinoco Basin falls under Venezuelan jurisdic-

tion, whereas the rest is Colombian. The river traverses some 2,148 km in

its journey to the sea from its currently recognized source near Cerro

Delgado-Chalbaud in the ancient mountains of the Guyana Shield near the

border with Brazil. In my opinion, the true source of the Orinoco is the

Guaviare River, which originates in the Andes of Colombia and contributes

much more water than the Ventuari. In any case, the Orinoco flows west from

its Venezuelan source, at first descending through dense tropical forest

that grows in the well-weathered rocky drainages of the Guyana highlands.

After sharing a portion of its reddish-brown waters with the Amazon via the

Casiquiare Channel, it receives its first major tributary, the Ventuari, and

then veers north to run along the northwestern edge of the Guyana Shield

where it marks the boundary between Colombia and Venezuela. Several major

tributaries enter the Orinoco from Colombia in this stretch (fig. 1), among

the largest of which are the Guaviare, Vichada, Tomo and Meta. At Puerto

Piez, the Orinoco turns slightly to the east, and receives the black waters

of the Cinaruco and Capanaparo rivers that drain the grassland savannas of

southern Apure state. Rocks of the Guyana Shield still project though sandy

bottom sediments at this stage. Gradually, the river bends more eastward.

Just before reaching Caicara, the muddy waters of the Apure River dump



















































































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their Andean sediments into the main channel of the Orinoco. Since the

Orinoco is often full during peak flood of the Apure, it tends to hold back

the waters of the Apure, and has formed an interior delta where vast areas

flood each year. The Orinoco changes course at this point to run in a

northeasterly direction towards the sea. It is bordered by the semi-arid

central plains to the north, and the humid Guyana Shield to the south. It

picks up vast quantities of black waters from the Caura and Caroni rivers

before it enters its highly productive delta and flows into the Atlantic

Ocean just south of the island of Trinidad. The average annual outflow is

about 33,000 m3/s (Zinck 1977). The Amazon, by way of comparison, delivers

an annual average of about 175,000 m3/s (Smith 1981).

The Apure River drainage lies mostly within 7" and 10 North lati-

tudes, and 66" and 720 West longitudes. It is Venezuela's largest tributary

(in terms of drainage area) of the Orinoco (fig. 2a & 2b) and drains 167,000

km2, or nearly 15% of the total area of the Orinoco Basin. Its average flow

of nearly 2000 m3/s (Zinck 1977) divided by the drainage area gives a figure

of about 378 mm/year runoff, which is about 24% of the mean precipitation

(Saunders & Lewis 1988a). It is exceeded in Venezuela by only two other

tributaries, both blackwater rivers from the nutrient poor soils of the

Guyana Shield, where rainfall is much higher. The Caroni River, which

drains some 93,000 km2 delivered over 4,000 m3/s before the enormous Rail

Leone (Guri) Dam was built. The Caura River, slated for future hydroelec-

tric development, carries 2,700 m3/s. The Guaviare River which drains

159,500 km2 and the Meta River with 103,000 km2 are two of the major Orinoco

tributaries in Colombia (Zinck 1977). The headwaters of the Apure drain the

southeastern flank of the Andes, and are located approximately 800 km by

river from the Orinoco River. Over 15% of the drainage is mountainous






















































































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(above 500m in elevation). Transit time from the Andes to the Orinoco

varies seasonally in the range of one to four weeks (Saunders & Lewis

1988a,b). On the way, the numerous branches of anastomosing rivers cross

the llanos, flat alluvial plains that formed in the late Pleistocene over

older marine sediments. In the wet season, most of the lower part of the

drainage is inundated by sheet flooding. The floodplain of the Apure is

much more extensive than that of most rivers. An internal delta of about

5000 km2 forms where the Apure and the Arauca (the first major tributary of

the Orinoco to the south) flow into the Orinoco. When discharge is high in

the Orinoco, a large inland sea forms between the mouths of the Capanaparo

river (the next Orinoco tributary to the south) and the Apure. The alter-

nation of wet and dry seasons causes annual changes in river level of about

six to eight meters. Using river level values from San Fernando de Apure,

Saunders & Lewis (1988a) defined four hydrologic phases to describe the

relationship between the river and the floodplain. The river is not in

contact with the floodplain during the first, low-water phase, which corre-

sponds to stage heights below 38 m. The rains, which usually start in

April or May, initiate the second, rising-water phase, during which the

river is still within its banks (38-42m). The inundation phase commences

when stage heights surpass 42m, and river water floods onto the surrounding

floodplain. Flooding usually begins in July, and peaks in September or

October. When the dry season sets in and water levels drop to below 42m,

the fourth, or falling-water phase begins (42-38m).

Of all of the Orinoco tributaries, the Apure is by far the most acces-

sible, with good, all-season roads crossing all of its major drainage sys-

tems. This factor alone was enough to select it as my study site, but in

addition to easy access the climate and topography are extremely





11

diverse. As a result, many different aquatic biotopes are included in the

drainage. There are cold mountain streams that tear through the Andes

at breakneck speeds; tepid, blackwater lowland swamps; large "white-

water" muddy rivers that meander slowly through the lower llanos (a

Venezuelan term for plains or savanna); and all the varied intergrada-

tions of these that can be imagined. The good roads in this region owe

their existence to the fertile soils and resultant extensive agriculture

that has developed. Deforestation has proceeded virtually unchecked

since colonial times. As more and more forests give way to pastures and

crops, the aquatic fauna becomes increasingly degraded. Massive fish

kills occur almost as a matter of routine when the first rains fall

after the months of drought and wash the accumulated pesticides and

fertilizers into the drainage in one large dose. Natural aquatic habi-

tats are disappearing rapidly and fish populations are suffering accord-

ingly. This too gave the Apure drainage a high priority as a study

area, inasmuch as the fishes sensitive to these changes may not be

around indefinitely.

Another factor in the selection of the Apure drainage is that the

Apure River and its larger tributaries support a large commercial fishery,

and provide a significant source of protein and extra income for rural

families. Almost no basic biological data is available for most species.

Declining catches in recent years and local conflicts over the best use of

aquatic resources in the region has local and federal governments concerned.

Most commercial species are migratory, moving in tune with the drastic

seasonal changes in water level and flow because of the accentuated wet

and dry seasons typical of the western llanos. Funding for impact

studies of local dams on commercial species helped pay for the sampling.








The Andean piedmont was characterized as an area of recent speciation

by Mago L. (1978), but Andean piedmont rivers, flowing out through narrow

valleys into the plains, offer excellent opportunities for hydroelectric

power generation. The Venezuelan government, eager to diversify its energy

resources now that the end of their vast petroleum wealth is in sight, has

projects for dams on almost every major piedmont river system. These dams

have denied the commercial species, particularly the coporo, Prochilodus

maria, access to the upland piedmont and montane lotic systems, and disrupt

the annual cycle of flood and drought used by migratory species as the cue

to make their moves. Commercial species populations are on the decline

throughout the Apure drainage, but direct causes are not easily identified

because of the wide array of concurrent negative impacts that are occurring.

As the commercial fish catch drops, concern is mounting, and governmental

interest in finding a solution is growing. But again, lack of basic infor-

mation about fish populations and ecology hinders progress.

In his seminal work, "Lista de los Peces de Venezuela incluyendo un

Estudio Preliminar sobre la Ictiogeografia del Pais," Mago L4ccia (1970)

lamented the deplorable state of knowledge of the Venezuelan freshwater fish

fauna. He noted that most of the pioneering ichthyological works of Eigen-

mann, Steindachner, Regan, Kner, Pellegrin, Norman, Fowler and others were

based on specimens from just about everywhere in South America except Vene-

zuela. Only the Maracaibo Basin, studied in detail by Leonard P. Schultz

(1944a & b, 1949), was relatively well known. Since then, the pace of

ichthyological research in Venezuela has quickened considerably. This is

principally due to the work of Dr. Mago L. and his students, but contribu-

tions have also been made by Agustin Fernandez YUpez, Felipe Martin and

Manuel Ramirez. However, the present state of knowledge on the freshwater








fishes of Venezuela is far from complete, and most areas still need to be

better sampled.

Neotropical characiform fishes have received considerable attention

from ichthyologists. C. H. Eigenmann provided the basis for most modern

studies with a series of papers published in the late 1800's and early

1900's that culminated in several huge tomes such as his American Characidae

series. Other workers such as E. Ahl, J. B6hlke, H. Fowler, J. Gdry, J.

Hoedeman, R. von Ihering, W. Ladiges, K. Luling, S. Meek, H. Meinken, N.

Menezes, G. Myers, A. and R. Ribeiro de Miranda, T. Roberts, H. Travassos,

S. Weitzman and R. Vari have continued the effort to give us a much better

idea of the tremendous diversity of form and function represented in this


group.













MATERIALS AND METHODS


Collecting

Many different collecting methods were employed, but most collections

were made with small, fine-meshed seines. Gill nets (both multifiber nylon,

and monofilament), beach seines, cast nets (both fine and commercial mesh

sizes), hand nets, and small otter trawls (in the Apure River's main chan-

nel) were also used. We also fished with electrofishing gear, rotenone, and

hook and line. Some specimens were obtained from commercial fishermen.

Fishing effort was not vigorously controlled at each site. Usually

sampling continued until no new species appeared. From 1977 to 1989 we

made a total of 875 collections in the Apure drainage (fig. 2b).

Curation

Specimens were preserved in 10-15% formalin solution, and later trans-

ferred to either 50% isopropanol, or 70% ethanol. Larger specimens were

usually slit on the right side to ensure complete preservation.

Material Examined

Most of the specimens examined as part of this study have been depos-

ited in the Museo de Ciencias Naturales de la UNELLEZ--Guanare (MCNG).

Additional material is deposited in the Field Museum of Natural History in

Chicago (FMNH), the museum of the Illinois Natural History Survey (INHS),

the Museo de Biologfa de la Universidad Central de Venezuela in Caracas

(MBUCV), the museum of Sacramento State College, in Sacramento California

(SSC), the Texas Memorial Museum in Austin (TMM), the Florida Museum of






Natural History in Gainesville (UF), and the United States National Museum

(USNM) in Washington. Other museum acronyms used in this study are:

AMNH--American Museum of Natural History; ANSP--Academy of Natural Sciences,

Philadelphia; BMNH--British Museum of Natural History; CAS--California

Academy of Sciences; CM--Carnegie Museum (now mostly in FMNH and CAS);

IU--Indiana University (these specimens are now located mostly in FMNH or

CAS); MCZ--the Museum of Comparative Zoology at Harvard; MNHN--Musdum

National d'Histoire Naturelle, Paris; MZUSP--the Museum of Zoology of

the Sao Paulo University in Brazil; NMW--the Vienna Natural History

Museum; SU--Stanford University (now at CAS, and designated CAS-SU);

ZMA--Zoologisch Museum of Amsterdam; ZMB--Zoologisch Museum of Berlin.

Format

The following format has been used to organize the information pre-

sented here. A brief introduction summarizing pertinent data for each

family is followed by a key to the species known to be present in the Apure

drainage. These sections are followed by the species accounts, which are

arranged, in sequence, under the following headings:

1. Genus--species--author--year (centered at top).

2. Common Name in Spanish & Common Name in English (if known).

3. Fig. #. This is the figure numbers) of the illustrationss.

4. Map: fig. #. This is the figure number of the dot map showing the

Apure drainage distribution.

5. Couplet. #. The couplet(s) where the species keys out is given.

6. Generic synonymy. This section, given as part of the species account

for the first species of each genus, includes the principal elements of a

generic synonymy: original name, describer, date, and type species. Only

primary junior synonyms are listed.






7. Specific Synonvmy. The specific synonymy includes the original name,

describer, date, and page number, as well as the type locality (only given

for citations of original descriptions), junior synonyms, and selected

references to Venezuelan specimens or other important reports. It is not

intended as a complete synonymy, but in many cases it may be. In most cases

synonymies have been copied from the literature. When the original descrip-

tion has been seen by me (many are in unavailable literature) this is so

indicated (as: seen).

8. Types. If readily available, museum location of the type material is

presented.

9. Comments. Comments are given on the taxonomic status of the species.

A synopsis of recent opinions on the status of the species or an explanation

of the validity of the name used is often presented.

10. Etymology. The semantic roots or origin of the scientific name

are explained.

11. Description Usually just a subheading is given here.

12. Illustrations. All original illustrations in this report are listed

first, followed by references to selected illustrations of the species

available in the literature. The illustrations are not intended to portray

detailed anatomy (for example fin-ray counts) of the species, but rather

give an overall impression of the species' basic morphology.

13. Diagnosis. A brief diagnosis of each species is given.

14. Size. The maximum size, as well as the size range of specimens usually

encountered are given.

15. Morphology. This section provides a brief physical description of

the most notable anatomical features of each species that are not mentioned

in the diagnosis.






16. Counts. Fin ray and scale counts are usually given. In most cases

only the range is given, but sometimes detailed counts are presented as the

count followed by the number of fish counted; for example: AR: 22(9) means

a count of 22 anal-fin rays was obtained for nine specimens examined.

The following abbreviations are used: DR--Dorsal Rays; AR--Anal Rays;

PR--Pectoral Rays; VR--Ventral or Pelvic Rays; LS--Lateral Scales;

LLS--Lateral-Line Scales; PDS--Predorsal Scales; TS--Transverse Scales,

(this is sometimes divided into scales above and below the lateral line;

CPS--circumpeduncular scale count; GR--gill rakers (if not indicated as

the total count of both upper and lower limbs, the figure given is the

count of the rakers found on the lower limb of the outer gill arch).

17. Measurements. Common body measurements are presented. The following

abbreviations are used: SL--Standard Length; TL--Total Length; GBD--Great-

est Body Depth; PDL--Predorsal Length; HL--Head Length; EYE--Eye Diameter;

SNT--Snout Length; IO--Interorbital Distance.

18. Pigmentation. Life colors are usually given along with pigmentation

patterns that remain in preserved specimens.

19. Distribution and Natural History Comments that don't fit into other

sections are given here.

20. Range. The overall geographic range is given.

21. Apure Distribution. Map: fig. #. The number of the distribution map

for each species is given. In these maps, the collection localities are

plotted on a base map of the Apure drainage. Map scale sometimes required

that more than one locality be represented by a single dot. Brief comments

on the distribution within the Apure drainage are usually given. One should

bear in mind that dot maps of species distribution do not take into account

the fact that a few species in the Apure drainage are migratory, and thus







may be present in some areas during only part of the year. Also, non-

migratory species will spread out onto the floodplain in the wet season.

22. Habitat. A brief summary of the types of water bodies occupied by

the species is given.

23. Abundance. This is a somewhat subjective classification scheme, since

collection effort was not standardized to allow actual abundance data to be

calculated. I plotted the number of characid species versus the number of

collections, then arbitrarily drew separations between four categories as

follows:

RARE: If found in 1 to 5 collections.

UNCOMMON: If found in 6-25 collections.

COMMON: If found in 25-200 collections.

ABUNDANT: If found in more than 200 collections.

As indicated, these data are not quantitative, since fishing effort

varied considerably from site to site and not all specimens of each species

were preserved (especially true of the larger, more common species). Also,

the number of collections may include repeats from the same site. However,

the results are useful as a first approximation, and when used in conjunc-

tion with the distribution maps they usually reflect a fairly accurate

picture of relative abundance, or at least ease of capture.

24. Number of specimens examined. This is the total number of specimens

collected in the Apure drainage as part of this investigation. It does not

include specimens examined from other collections.

25. Food. Species are usually classified as CARNIVORE, HERBIVORE,

OMNIVORE or DETRITIVORE, and the major items that comprise each species

diet are listed if known. This section is based on my own field obser-

vations of live fishes and from stomach content analyses reported in




19

the literature, or done by myself, Dr. Craig Lilyestrom, Dr. Kirk

Winemiller or Mr. Leo Nico in our lab at UNELLEZ in Guanare.

26. Reproduction. Most of these data are from the literature, or

from data gathered by Dr. K. Winemiller for his doctoral research and

that was briefly summarized by Winemiller & Taphorn (1989). I use the

terminology introduced in that paper to classify the reproductive

strategy of each species:

"K-strategy" is characterized by high juvenile and adult survi-

vorship, low fecundity, a long life and generation time (the time from

birth or hatching to reproductive maturity), iteroparity (spawning

several times per season) and a relatively stable population density

throughout the year.

"rl-strategy" is characterized by low juvenile and adult survi-

vorship, low fecundity per individual but repeated spawning bouts

(iteroparity), a short life and generation time, and variable popula-

tion densities throughout the year.

"r2-strategy" is characterized by low juvenile but high adult

survivorship, a high fecundity, a long life, semelparity (spawning all

at once, once per season) and by great fluctuations in the population

density.

27. Migrations. There are no comprehensive studies of migration of the

fishes in the Apure Drainage, but we are currently investigating the migra-

tion and life cycle of the coporo, Prochilodus mariae (Barbarino D. &

Taphorn 1989). Local fishermen also provided information.

28. Importance. The commercial, sport, and ornamental uses as well as

the harmful or dangerous aspects of each species are discussed in this

section.




20

If no information is available on a given topic, that section is

omitted from the species account.

An abbreviated list of the material examined (the number of lots

or jars and the total number of specimens) is given for each species in

the Appendix. A more detailed list of specimens examined and locali-

ties is available from the author. All specimens are deposited in the

Collection of Fishes, Zoological Musuem, Museo de Ciencias Naturales de

Guanare, at UNELLEZ, in Guanare, Venezuela.

Each family is presented in a separate section, and appears in

alphabetical order. A brief diagnosis of the family, with comments on

the number of species and their general ecology is followed by a key to

the species of the Apure drainage and the individual species accounts.

In some keys additional information useful for identification, follows

the species name in brackets.













RESULTS


After many years of sampling (1977-1989), during which some 875

collections were made in the Apure drainage, over 14,000 lots of specimens

have been processed, cataloged and identified. I have identified 354

species of fishes, belonging to 41 families (Table 1). The so-called

ostariophysans strongly dominate the fauna, and comprise 305 (86%) of the

354 species. The ostariophysans have the anteriormost four or five verte-

brae fused and include, among South American groups, the orders Characi-

formes, Gymnotiformes and Siluriformes. The vast number of fishes col-

lected and data generated by the project have made it necessary to limit

this dissertation to a subset of the total fish fauna. The order Characi-

formes was selected because of its great diversity, and a somewhat larger

volume of literature that is available for identification of the species.

This order includes 13 (32%) of the 41 families and 138 (39%) of the

species (Table 1). Only the order Siluriformes, with about 137 species,

matches the characiform fishes in diversity in the Apure drainage. The

taxonomy of South American fishes is still relatively poorly known, and

has been likened to the situation in North America 100 years ago. As more

collecting is done, and taxonomic revision continues, the total number of

species per family will continue to change, but the relative numbers of

species per family will probably not vary as greatly, except perhaps in

the order Gymnotiformes, which will probably outstrip the others in terms

of new species described.







Composition of the Apure River Drainage Fishes.


Order

1 RAJIFORMES


2 CLUPEIFORMES


3 SALMONIFORMES*

4 CHARACIFORMES












5 SILURIFORMES


6 GYMNOTIFORMES





7 ATHERINIFORMES


8 SYNBRANCHIFORMES

9 PERCIFORMES


Family

1 Potamotrygonidae

2 Clupeidae
3 Engraulidae

4 Salmonidae

5 Anostomidae
6 Characidae
7 Characidiidae
8 Chilodontidae
9 Ctenoluciidae
10 Curimatidae
11 Cynodontidae
12 Erythrinidae
13 Gasteropelecidae
14 Hemiodontidae
15 Lebiasinidae
16 Parodontidae
17 Prochilodontidae

18 Ageneiosidae
19 Aspredinidae
20 Astroblepidae
21 Auchenipteridae
22 Callichthyidae
23 Cetopsidae
24 Doradidae
25 Hypophthalmidae
26 Loricariidae
27 Pimelodidae
28 Trichomycteridae

29 Apteronotidae
30 Electrophoridae
31 Gymnotidae
32 Hypopomidae
33 Rhamphichthyidae
34 Sternopygidae

35 Belonidae
36 Rivulidae
37 Poeciliidae

38 Synbranchidae

39 Cichlidae
40 Sciaenidae


10 PLEURONECTIFORMES 41 Soleidae


Species
Family
4


per
Order
4


% of Total
1.1


5 1.4


1 0.2


38.9












38.9


31 8.7


10 3.0


1 0.2

25 7.0


2 0.6


Table 1.







Characiformes

Characiform fishes are ostariophysans, the group of fishes that

dominates freshwater habitats in most of the world. Ostariophysans are

combined into a group because they all have the first few vertebra modi-

fied and linked to the surface of their bodies by a series of modified

bones to form what is presumed to be a listening device, or vibration

detector. Characiforms have gone farther with this device than most of

their cousins the catfishes, knifefishes, carps and suckers (the other

ostariophysans). They have developed a complete Weberian apparatus in

which the tripus is connected to the body of the third vertebra by means

of a vibrating lamina. This mechanism presumably transmits sounds or

vibrations picked up on the gas bladder to the inner ear (GUry 1977).

Better hearing could perhaps account in part for the dominance of the

ostariophysans in most freshwater ecosystems of the world (Fink & Fink

1981). Weitzman (1954, 1962) provided an extensive osteological defini-

tion of characiform fishes and Fink & Fink (1981) discussed their rela-

tionships with the other ostariophysans. The group is so diverse morpho-

logically that they tend to defy succinct definition. About all one can

say is that they all have scales and teeth on the jaws or lips! Actually,

not even that is true of all characiforms since a few species from the

high Andes in southern South America have lost their scales completely and

the Curimatidae are toothless (at least as adults; juveniles have teeth in

the early developmental stages). Many are small schooling species that

have a chemoreceptory sensory system that, upon detection of substances

released by school members under attack or stress, will trigger a "fright

response," causing the school to adapt defensive maneuvers.







No consensus has yet been reached by workers on characiform upper-

level taxonomy. For many years almost all characoids were lumped in the

family Characidae (Eigenmann 1917, Weitzman 1962). The group was subdivided

by Greenwood et al. (1966), which (for Characiformes) is based largely on

the findings of Dr. Stanley Weitzman. Since then, the group, and the divid-

ing lines between the families and subfamilies, have been topics of constant

investigation, and debate. Gdry (1977) proposed several modifications. In

Table 2 the two schemes are contrasted for South American groups.


Table 2. Comparison

Greenwood et al.

(12 families)

Characidae

Characidae

Characidae

Characidae

Erythrinidae

Ctenoluciidae

Cynodontidae

Lebiasinidae

Parodontidae

Gasteropelecidae

Prochilodontidae

Curimatidae

Anostomidae

Hemiodontidae

Chilodontidae


of family level taxonomy of Characiformes.

Gdry Used Here

(11 families) (13 families)

Characidae Characidae

Characidiidae Characidiidae

Serrasalmidae Characidae

Crenuchidae Characidae

Erythrinidae Erythrinidae

Ctenoluciidae Ctenoluciidae

Characidae Cynodontidae

Lebiasinidae Lebiasinidae

Hemiodidae Parodontidae

Gasteropelecidae Gasteropelecidae

Curimatidae Prochilodontidae

Curimatidae Curimatidae

Anostomidae Anostomidae

Hemiodidae Hemiodontidae

Curimatidae Chilodontidae







Thus, the scheme of Greenwood et al. (1966) would leave South America

with 12 families of Characiformes to Gdry's 11. In more recent works, some

of these families have been promoted to familial or demoted to subfamilial

rank. Weitzman & Gdry (1981) defined the Characidiinae. Nelson (1984)

listed Cynodontinae (which he earlier [1976] recognized as a family), as a

subfamily of Characidae; Vari (1989) treated it as a tribe of the Characi-

dae. Other groups have had the familial limitations better clarified and

justified, as for example Vari's (1983, 1989) treatment of Curimatidae,

Prochilodontidae, Anostomidae and Chilodontidae. Nelson (1984) included

only eight families: Hemiodontidae, Curimatidae, Anostomidae, Erythrini-

dae, Lebiasinidae, Gasteropelecidae, Ctenoluciidae and Characidae, thus

demoting again the Prochilodontidae, Cynodontidae, Parodontidae and

Chilodontidae. Changes will continue. Except for the recognition of the

family Characidiidae, I have followed the classification of Greenwood et

al., for a total of 13 families. The correct spellings of Hemiodontidae

and Chilodontidae (vs Hemiodidae and Chilodidae) are also as yet unre-

solved. The type genera are Hemiodus and Chilodus.

I have adopted this system as a matter of practical convenience. This

should not be interpreted as support for any particular position in the

controversy of higher level relationships of characiforms. For convenience,

and since taxonomic affinities are as yet unresolved at various levels, the

families, genera and species are discussed in alphabetic rather than taxo-

nomic order.

The characiform fishes exhibit an incredible diversity of form

and occupy a wide array of ecological niches. Eigenmann (1917), Weitz-

man (1962) and Fink & Fink (1981) all marveled at the incredible explo-

sive radiation of this group in South America, which surpasses that of







the marsupials in Australia. Although many families contain widely

diverging morphotypes, I will try to briefly characterize each.

The Characidae comprises the most morphologically diverse group and

also includes the largest number of species. Although most species are

small minnow-like tetras ("sardinas" in Venezuela), this family includes

the piranhas, giant pacus, pike characins, strange tusked scale-eaters,

tiny killyfish-like inhabitants of blackwater streams, neon tetras, silver

dollars and palometas, and South American characid versions of trout,

salmon, clupeids and anchovies. The Erythrinidae is a small family of

large to medium fishes that are cylindrical, bowfin-like predators, typi-

cal of shallow lentic habitats. The Ctenoluciidae is represented by only

a few species of elongate gar-like surface predators. Cynodontids are

large, riverine predators with keeled, compressed bodies, large eyes and

expanded pectoral fins adapted to life near the surface in strong cur-

rents. Their extremely large canines give these piscivores a particularly

fierce appearance. Lebiasinids include two divergent groups: the "Creole

carps," Lebiasina, are medium-sized predators that inhabit mountain

streams, whereas Pvrrhulina and relatives are small, colorful fishes

typical of vegetation-choked lowland ponds. The Characidiidae and Paro-

dontidae include ecological equivalents of North American darters, adapted

to life in the riffles or mountain streams. The hatchetfishes of the

family Gasteropelecidae are bizarre, insectivorous, surface-dwelling

fishes with incredibly expanded coracoid bones (Weitzman 1954, 1960), and

very large pectoral-fins that, when rapidly vibrated, give these fish the

ability to "fly." Prochilodontids and curimatids are medium to large

sized fishes reminiscent of carps and suckers. They feed on mud, algae

and detritus, and comprise a large percentage of the biomass in most







tropical waters. They frequently support productive local commercial

fisheries. Many species make spectacular annual migrations to feeding or

breeding grounds. Anostomids and hemiodontids include mostly herbivores

and planktivores, with fusiform bodies and conical heads adapted to swim-

ming in fast currents. The chilodontids are small to medium-sized head-

standers similar to the curimatids, but with teeth.

The differing, still varying taxonomic classifications of characi-

forms exist primarily because current taxonomic groups for the most part

reflect different authors' attempts to group morphologically similar taxa

together. Differing opinions as to exactly which characters are "similar"

and which are not leads to different conclusions. Although Eigenmann

(1917) expressed much concern about the monophyly of the numerous upper

level taxa he described, the methodologies available at that time were

inadequate. He remarked that the tremendous "radial adaptation" of char-

aciform fishes was at once a paradise for evolutionary biologist and a

nightmare for taxonomists seeking a useful system of names. Durbin Ellis

(1918) came to the conclusion that the genera Hyphessobrvcon and Hemiqram-

mus were conveniences, and not natural entities (ie. monophyletic units).

Recent efforts, such as those as Vari (1989), to base taxonomy on shared

derived characters and that reflect the phylogenetic history of the fishes

would seem to be the only approach that might eventually lead to agreement

among taxonomists instead of continuing controversy. The characiform

families, and especially the Characidae, contain such divergent groups of

fishes that it is difficult to write a key that is both easy to use and

reasonably precise. The following key should work for most individuals of

most species currently known from the Apure drainage. Readers are also

referred to Taphorn & Lilyestrom (1984) for keys to all the freshwater

families in Venezuela.







Key to the Characiform families present in the Apure River drainage.

la. Lips and jaws completely lacking teeth of any kind...

CURIMATIDAE

lb. Teeth present on jaws or lips (teeth on lips may be small and

difficult to see without magnification)... ...2

2a. (Ib) Teeth present only on lips, none on jaws ...3

2b. Lips without teeth; upper or both jaws with teeth... ...4

3a. (2a) Gills normal; mouth large and evertible to form a round,

sucking disk; teeth present on edges of lips, teeth small, comb-

like and numerous (many more than 20 on either side), arranged in

single row at sides of lips, and in two rows near center midlinee)

of lips; predorsal spine present, embedded in flesh just anterior

to dorsal fin; large species that exceed 200 mm SL in the first

year of growth... PROCHILODONTIDAE

3b. Gills with fourth arch dilated (expanded), its surface with folds

and wrinkles that mesh with fifth arch; mouth small, not complete-

ly evertible; teeth larger, not very numerous (less than 20 per

jaw), in single row; no predorsal process present; small species
that seldom exceed 200 mm SL CHILODONTIDAE

4a. (2b) Lower jaw without teeth, or without teeth at center (near

symphysis)... ...5

4b. Lower jaw with complete series of teeth... ...6

5a. (4a) Teeth of upper jaw arranged in semicircle; pectoral fins

not greatly expanded, usually not as long as head; cranium without

fontanels; lower jaw never with teeth at sides, usually completely

lacking teeth... HEMIODONTIDAE







5b. Teeth of upper jaw arranged in straight line; pectoral fins

greatly expanded, usually longer than head; cranium with large

fontanels; lower jaw usually with a few teeth at sides...

PARODONTIDAE

6a. (4b) Lower jaw trapdoor-like, with extremely large canine teeth,

(the length almost equal to or surpassing eye diameter) that fit

into special "sockets" present in upper jaw and cranium when mouth

is shut... CYNODONTIDAE

6b. Lower jaw without extremely large canines, sometimes with small

canines that measure less than one third of eye diameter, but

usually with multicuspid teeth... ...7

7a. (6b) Adipose fin present... ...8

7b. Adipose fin absent... ...13

8a. (7a) Scales ctenoid; jaws extremely elongate and anal fin with

fewer than fifteen rays... CTENOLUCIIDAE

8b. Scales cycloid; jaws usually not extremely elongate, but if so,

anal fin with more than 15 rays... ...9

9a. (8b) Branquial membranes fused to isthmus for nearly their entire

length; mouth with 6-8 large rabbit-like, sometimes unusually

shaped incisors... ANOSTOMIDAE

9b. Branquial membranes free from isthmus; teeth variable, but not

usually as above... ...10

10a. (9b) Chest bones (coracoids) greatly expanded to form a deep

narrow keel; dorsal-fin origin behind that of anal fin; lateral

line short, usually directed down towards anal fin origin; pec-

toral fins greatly enlarged for flight...

GASTEROPELECIDAE







10b. Chest usually not greatly expanded, but if so, then dorsal-fin

origin is at a level with, or in front of that of anal fin;

lateral line, if present not usually directed down towards

anal-fin origin; pectoral fins variable... ...11

Ila (lOb) Lower jaw with two rows of tricuspid teeth (the second row

of small teeth sometimes difficult to see); upper jaw with only

one row of tricuspid teeth and without conical or canine teeth...

LEBIASINIDAE (Lebiasina)

lib. Teeth not as described above... ...12

12a. Pectoral and pelvic fins enlarged, inserted very low on body and

directed under chest (to support fish resting on substrate);

pectoral fin with the first three or four rays thickened and

unbranched; premaxillary teeth always in a single row; chest and

abdomen flattened (adapted to benthic life as in North American

darters); head conical; mouth small usually subterminal to ventral

(but terminal in a few species)...CHARACIDIIDAE (in part)

12b. (lib) Pectoral and pelvic fins not particularly expanded, usually

inserted near or just below midbody, (pectorals not used to

support body when resting on substrate); first three or four rays

not thickened, usually only first one or two unbranched; premaxil-

lary teeth in one to three rows, but usually two; chest and abdo-

men rounded; head not usually conical; mouth variable...

CHARACIDAE (in part)

13a. (7b) Large (up to 1000 mm SL) predators with wide terminal mouths

armed with canine teeth on premaxilla and dentary, and sometimes

on maxilla; scales relatively large (some nearly size of eye)...

ERYTHRINIDAE







13b. Small (less than 40 mm SL) fishes with small, superior or

terminal mouths that lack large canine teeth (teeth usually small

to moderate in size, conical or multicuspid); scales relatively

small... ...14

14a. (13b) Dorsal fin origin posterior to that of anal fin; males

with long filamentous extension on opercle...

CHARACIDAE (Corvnopoma)

14b. Dorsal fin origin anterior to that of anal fin; males lacking

opercular filament... ...15

15a. (14b) Mouth terminal or subterminal; dorsal fin with fifteen or

more rays; sides with alternating light and dark vertical bars...

CHARACIDIIDAE (Elachocharax)

15b. Mouth superior; dorsal fin with fewer than fifteen rays; sides

without vertical bars... LEBIASINIDAE (pyrrhulinines)

Anostomidae

The anostomids characteristically are fusiform, somewhat elongated

fishes with conical heads, distinguished from other families by their small,

nonprotractile mouths that usually have eight large incisors arranged in a

single row in either jaw. The anterior nostril is usually tubular, and the

gill membranes are often united to the isthmus (Gdry 1977). According to

Winterbottom (1980), this family together with the Chilodontidae, shares

posteriorly replaced, cuspid pharyngeal teeth (not to be confused with the

pharyngeal teeth of Cyprinidae). Roberts (1969), Gery (1977), Winterbottom

(1980) and Vari (1983) have presented very different concepts of subfamilial

divisions within the Anostomidae. The family comprises about ten genera,

many of which are monotypic. All told, there are at least 100 described





32

species (Gdry 1977), of which the largest by far is Leporinus, with some 70

nominal species (Vari 1983).

Most of the remaining taxonomic problems in this family involve the

genus Leporinus, since Winterbottom's (1980) work has cleared up the

situation in the subfamily Anostominae (comprising the genera Anostomus,

Pseudanos, Gnathodolus, Sartor, and Svnaptolaemus). Neither he nor Vari

(1983) defined for the remaining genera, Abramites Abramoides, Laemolvta,

Leporellus, Leporinus, Rhytiodus and Schizodon, although Winterbottom

(1980) rejected Gery's (1977) subdivision into two subfamilies, Leporelli-

nae for Leporellus, and Anostominae for all the rest.

The majority of anostomids are medium to large-sized omnivores or

vegetarians that use their incisor-like teeth to clip aquatic vegeta-

tion, or as forceps to remove prey from crevices. A few anostomids

have developed feeding specializations, these species are relatively

smaller in size, are more elongated and have minute upturned mouths,

often with bizarre dentition.

I have been able to identify twelve species from the Apure drainage,

half of them members of the genus Leporinus. Most of the species'

identifications are still tentative. For those that don't seem to agree

with any described species, I have used code names.

Very little natural history information is available on anosto-

mids in the Apure drainage. Most species are probably omnivorous,

though some like Schizodon isoqnathus tend to be more herbivorous. All

are probably egg scatterers, with no parental care. It is expected

that most of the medium to large species spawn annually at the onset of

the rains. The smaller ones probably spawn repeatedly during the wet

season.







Key to the Apure Drainage Species of Anostomidae

This key is based in part on Winterbottom (1980) and Gery (1977),

and will work only for specimens with adult pigmentation patterns.

Since there is considerable size range variation in the family, defining

"juvenile" size for all anostomids is not possible. Juvenile Anostomus

for example, probably obtain adult coloration at a size of 20-30 mm SL,

whereas juvenile Leporinus may not change to the adult pattern until

they reach 100-120 mm. Juveniles all tend to look alike, and are

marked with numerous vertical bars and rounded midlateral spots, that

are gradually lost as the adult pattern is expressed.

la. Caudal fin with oblique black bars; caudal fin densely scaled

for most of its length; anterior nostril not tubular, proximate

in position to the posterior nostril...

Leporellus vittatus (fig. 7)

lb. Caudal fin uniformly pigmented, without bars; caudal fin not

scaled; anterior nostril usually tubular and well separated

from posterior nostril... ...2

2a. (Ib) Mouth superior (i.e. upturned) in adults... ...3

(Note: small juvenile Schizodon isognathus have superior mouths

to a size of some 4 cm SL.)

2b. Mouth terminal or inferior in adults... ...5

3a. (2a) Pigmentation pattern comprising a large rounded black spot

surrounded by lighter area located on center of each side, a

smaller spot behind opercle and at base of caudal fin, dorsum

crossed by 8-11 irregular narrow black bars, sides with horizontal

rows of small spots... Pseudanos irinae (fig. 23)







3b. Pigmentation pattern not comprising a large rounded spot in center

on the side, but rather of several wide black stripes or one wide

black lateral stripe with several additional horizontal rows of

small dots ...4

4a. (3b) Pigmentation pattern consisting of 10-11 horizontal rows of

small dots on sides and a wide lateral stripe from opercle to tail

(fig. 21) Pseudanos gracilis (fig. 21)

Winterbottom (1980) noted that this species exhibits two color

phases. One is described here, whereas the other (not yet found

in the Apure drainage) consists of 3-4 large rounded spots on mid

sides with horizontal rows of small whitish spots. This is simi-

lar to the pattern of P. irinae; however, P. gracilis never has

horizontal rows of black dots nor dark thin bars crossing the

dorsum.)

4b. Pigmentation pattern consisting of wide black horizontal stripes

separated by narrower white stripes, the widest black stripe

centered on the side and extending from opercle to base of tail...

Anostomus ternetzi (fig. 5)

5a. (2b) Teeth incisiform, with 2-5 cusps, some multicuspid teeth

always present; anal fin usually with only seven branched rays...

Schizodon isognathus (fig. 25)

5b. Teeth incisiform, without cusps or at most bifid, never

multicuspid; anal fin with eight or more branched rays... ...6

6a. (5b) Anal fin usually with ten or more branched rays; body high

and compressed, GBD 37-48% SL; a postventral keel present;

headstanders that usually swim in a vertical position...

Abramites hypselonotus (fig. 3)







6b. Anal fin usually with nine branched rays or fewer; body terete, not

very compressed, GBD usually less than 30% SL; no postventral keel;

swimming position horizontal... (genus Leporinus, 6 spp.)... ...7

7a. (6b) Body with about seven, wide, black vertical bars, the second

usually forming a "Y"; base color yellowish...

Leporinus yophorus (fig. 19)

7b. Body without vertical bars, either plain, with horizontal stripes,

or with large spots; base color variable... ...8

8a. (7b) Body with 4-5 wide black horizontal stripes, separated by

narrower white or yellow stripes...

Leporinus cf striatus (fig. 17)

8b. Body without horizontal stripes, either plain with a small caudal

spot or with large rounded spots on sides... ...9

9a. (8b) Adults with plain brown body and a small black spot at base

of caudal fin... Leporinus sp. (fig. 13)

[lateral-line scales 42-44; predorsal scales 12-13; transverse

scales 13-14]

9b. Adults with large black spots on sides of body... ...10

10a. (9b) Adults with five or more large black spots on sides of body,

some along lateral midline, others both above and below these;

mouth inferior... Leporinus cf maculatus (fig. 9)

1Ob. Adults with only two to four large rounded spots, all along lateral

midline; mouth terminal or subterminal... ...11

11a. (lOb) Adults usually with only two large rounded spots along

lateral midline and no faint row of smaller spots on upper sides,

although faint vertical saddles cross dorsum; head and body deeper

and more robust; scales seldom spotted (one spot per scale); body







often decidedly higher in front of dorsal fin; eye smaller, in

specimens over 100 mm SL its horizontal diameter less than half of

interorbital width... Leporinus friderici (fig. 11)

[lateral-line scales 38-40; predorsal scales 9-12; transverse

scales 11-12]

11b. Adults usually with three or four large rounded spots along

lateral midline plus a faint row of smaller spots on upper sides;

scales often a spot (one per scale) arranged so as to form hori-

zontal rows of dots; head and body more slender, not decidedly

higher in front of dorsal fin; eye larger, in specimens over 100

mm SL its horizontal diameter is more than half interorbital

width... Leporinus sp. "aguaro" (fig. 15)

[lateral-line scales about 39; predorsal scales 10-12; transverse

scales 11-12]

Species Accounts

Abramites hypselonotus (Gunther) 1868

High-Backed Headstander Cabezibajo

Fig. 3. Map: fig. 4. Couplet 6a.

Generic synonymy

Abramites Fowler 1906:331 (type species: Leporinus hypselonotus GUnther

1868, by original designation); Vari & Williams 1987:89 (revision of

genus).

Specific synonymy

Leporinus hypselonotus GUnther 1868a:480 (type locality: Upper Amazon,

Xeberos, Peru); Steindachner 1882:12 (Ciudad Bolivar, Venez.);

Eigenmann 1909:323, 344 (Orinoco); Schultz 1944b:268 (Venez.).








































Figure 3.


Abramites hypselonotus.







Leporinus solarii Holmberg 1887:222 (type locality: Argentina, Rio

Parani).

Leporinus eaues Boulenger 1896:34 misidentification of L. hypselonotus

from Brazil).

Abramites hypselonotus Fowler 1906:331 (indicated as type species of

Abramites; 1950:249 (synonymy); Mago L. 1970:75 (Venez.); G6ry

1977:175 (key); Vari & Williams 1987:92 (synonymy, key, revision of

genus).

Abramites microcephalus Norman 1926:92 (type locality: near mouth of

Amazon River).

Abramites ternetzi Norman 1926:93 (type locality: Brazil, Matto (= Mato)

Grosso, Sao Luis and Descalvados.

Leporinus salarii Borodin 1929:288, (as a possible synonym of L.

hypselonotus, specific name misspelled).

Leporinus nigripinnis Meinken 1935:193 (type locality: Argentina,

Corrientes).

Abramites eaues FernAndez Y. 1950:116 misidentificationn, Rio

Salinas, Venez.); Mago L. 1970:75 (Venez.).

Abramites solarii Ringuelet, Aramburu and Alonso de Aramburu 1967:213.

Abramites hypselonotus ternetzi Gery 1977:175 (Rio Paraguay Basin).

Abramites hypselonotus hypselonotus Gdry 1977:75 (Amazon and Orinoco

basins).

Types. (designated by Vari & Williams 1987). Lectotype: BMNH

1867.6.13:40. Paralectotypes: BMNH 1867.6.13:41-42.

Comments. The genus Abramites is comprised of only two species. A.

hvyselonotus (GQnther 1868), the only species in Venezuela, has 10-12

branched anal-fin rays and eight, irregularly-shaped bars on the sides







between the nape and the caudal peduncle. A. eaues (Steindachner) 1878,

has 13-14 branched anal-fin rays and only five bars on the body, the

anteriormost situated under the dorsal fin (Vari & Williams 1987).

Etymology. ABRAM = from Abramis, a genus of similarly shaped fish,

ITES = like; HYPSELO = raised or high, NOTUS = back.

Description

Illustrations. Fig. 3; Axelrod et al. 1971:F-2.10; Vari & Williams

1987:figs. 2-5.

Diagnosis. The unusual body shape and pigmentation pattern (fig. 3)

are sufficient to identify this species. It is further distinguished by

a terminal mouth, a deep, compressed body (GBD 37-48% of SL), and the

presence of a postventral keel.

Size. It grows to about 130 mm SL.

Morphology. See Vari & Williams (1987). The conical head abruptly

expands vertically behind the eye and the dorsal profile rises steeply

from the nape to the dorsal-fin origin to give this species its charac-

teristic high-backed appearance. The body is more compressed than in

most anostomids.

Counts. DR 10-13 (up to three unbranched); AR 12-15 (up to three

unbranched); PR 13-15; VR 8-9, 37-38 vertebrae.

Pigmentation. The body is tan or silvery with eight irregular

vertical bars, the darkest and widest bar extends from the pelvic fins

across body and onto the anterior dorsal fin. There is also a black

stripe from the tip of the lower jaw through the eye, which continues

obliquely upward toward the dorsum. The adipose fin is yellow and

black, the caudal and pectoral fins are clear, and the anal fin is

black.

















































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Distribution and Natural History

Range. A. hypselonotus occurs in the Amazon, Orinoco, Paraguay and

lower Parand basins (Vari & Williams 1987).

Apure distribution. Map: fig. 4. Although few specimens were

collected, the localities range across the entire Apure drainage.

Habitat. This species was most frequently collected in habitats

with aquatic vegetation in quiet sidewaters of large whitewater rivers

in the low llanos. It swims in a head down position, often aligning

itself with the stems of plants.

Abundance. UNCOMMON.

Number of specimens examined. 28 from 14 collections.

Food. OMNIVORE. Its diet includes aquatic invertebrates, as well

as vegetable matter.

Reproduction. Probable strategy: rl.

Importance. This is a highly valued ornamental.

Anostomus ternetzi Fernandez Y. 1949

Red-Mouthed Headstander Cabezibajo Bocaroja

Fig. 5. Map fig. 6. Couplet 4b.

Generic synonymy

Anostomus Gronow 1763:122 (description and figure, no species mentioned,

work not accepted by ICZN).

Anostomus Scopoli 1777:451 (no species mentioned, but since this work

was based on Gronow the type species is that illustrated by Gronow

1756, which is Salmo anostomus Linnaeus).

Anostoma Rafinesque 1815 (alternative spelling).

Mormyrhynchus Swainson 1839:186, 291 (type species: Mormyrhynchus

gronovii Swainson = Salmo anostomus Linnaeus, by monotypy).







































































Figure 5. Anostomus ternetzi.


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Histriodromus Gistel 1848:8 (type species: Salmo anostomus Linnaeus,

by monotypy).

Pithecocharax Fowler 1906:319 (type species: Salmo anostomus Linnaeus,

by original designation, this name was proposed as a substitute for

Anostomus Walbaum 1792).

Specific synonymy

Anostomus ternetzi Fernandez Y. 1949:293 (type locality: Orinoco River

System); Knoppel 1972:231 (diet).

Anostomus anostomus (non Linnaeus); Myers 1950:184 (part).

Types. Holotype: Museo de Ciencias Naturales de Caracas 46001.

Paratypes: MCNC 46002; CAS 20093(1), 20094(1), 20095(4), 20096(1).

Etymology. ANO = upturned, STOMUS = mouth; TERNETZI = for Carl

Ternetz.

Description

Illustrations. Fig. 5; Axelrod et al. 1971:F-40.11 40.12; Gdry

1977:188; Winterbottom 1980:81 fig. 17.

Diagnosis. A. ternetzi is separable from Leporinus by the superior

mouth. The color pattern is distinctive for the species. The white

stripe that extends from between nostrils along the dorsal midline to

the dorsal-fin origin in this species, is dark in A. anostomus, a spe-

cies that occurs in other parts of Venezuela.

Size. It grows to about 100 mm SL.

Counts. This species has three branchiostegal rays instead of the

four usually found in other Anostomus species. DR 12-13; AR iii7-iii8;

PR i13-i15; VR i8; LS 39-42; PDS 11-14; CPS 16.

Pigmentation. The basic pigmentation pattern consists of three wide

black horizontal stripes separated by narrower white zigzag stripes.







The widest black stripe is situated at midside and extends from the

opercle to the base of the tail. Another starts at the pectoral-fin

insertion and extends back to the lower part of the caudal peduncle.

There is a narrow black stripe situated on either side of the narrow

white stripe that runs along the ventral midline, and another wide black

stripe on either side of the white stripe that extends from between the

nostrils to the dorsal fin origin. In many individuals the black (or

dark brown) pigment uniformly covers most of the dorsum, although it is

sometimes divided into several rows of dots by lighter areas. Fins that

are normally reddish in life, would appear clear in preserved specimens.

Distribution and Natural History

Range. This species occurs in the Amazon and Orinoco basins, and in

Guyana.

Apure distribution. Map: fig. 6. It is known only from northern

Apure state, and the Aguaro-Guariquito system.

Habitat. It is found in black or clearwater streams with abundant

aquatic vegetation, in the sandy-soiled areas of northern Apure state

and western Guirico.

Abundance. UNCOMMON.

Number of specimens examined. 69 from 19 collections.

Food. OMNIVORE. This fish probably feeds on vegetable material as

well as aquatic insects. It swims head down, and presumably feeds in

this position amidst aquatic vegetation.

Reproduction. Probable strategy: rl. Winterbottom (1980) noticed

some sexual dimorphism, in that males have a greater caudal peduncle

depth. Sterba (1972) stated that the similar A. anostomus is territori-

al. Axelrod et al. (1971) stated that in A. anostomus the pair quivered

























































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side by side, and expelled a large number of eggs all over the glass,

plants and the bottom of the aquarium. Fry were slender, about 15 mm

long, and swam in a normal horizontal position.

Importance. Ornamental.

Leporellus vittatus (Valenciennes) 1849

Stripe Tailed Leporellus Mije de Cola Rayada

Fig. 7. Map fig. 8. Couplet la.

Generic synonymy

Leporellus Lutken 1874b:129 (type species: Leporinus pictus Kner, by

monotypy).

Leporinodus Eigenmann 1922:116 (type species: Leporinodus retropinnus

Eigenmann 1922, by original designation, (described in footnote).

Specific synonymy

Leporinus vittatus Valenciennes in Cuvier & Valenciennes 1849:59 (type

locality: Rio Amazonas).

Leporellus vittatus Lutken 1874b:129; Fowler 1950:253 (synonymy);

Gery 1977:151 (diagnosis).

Leporinodus vittatus Eigenmann 1922:117.

Leporinus pictus Kner 1859:172, pl. 8, fig. 19 (type locality: Orissanga,

Est. de SAo Paulo).

Salmo cagoara Natterer in Kner 1859:172 (name in synonymy).

Leporinus maculifrons Reinhardt in LQtken 1874b:201 (name in synonymy).

Leporellus timbore Eigenmann 1922:117 (type locality: Rio das Velhas).

Comments. Gdry (1977) listed seven forms in this genus, of which

he listed (without explanation) L. maculifrons, L. timbore, and L.

cartledqei as synonyms of L. pictus. None are well known, and a revi-

sion of the genus is necessary before any further comments can be made















































Figure 7. Leporellus vittatus.


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about synonymies. I have used the synonymy of Fowler (1950) here, but

additional study may change these.

Etymology. LEPORELLUS = like a rabbit, referring to the teeth;

VITTATUS = spotted.

Description

Illustrations. Fig. 7; Gdry 1977:153.

Diagnosis. This is the only anostomid with a scaled, obliquely

barred caudal fin. The pigmentation pattern of the body (fig. 7) is

also distinctive.

Size. It grows to at least 200 mm SL.

Morphology. It is elongate with a large head and eye. The mouth is

subterminal with the lower lip reverted to form a wide fold. The gill

membranes are joined to the isthmus. The nostrils are proximate, and

not tubular (unusual in this family). The caudal fin is completely

scaled.

Counts. DR 13; AR 10-11; PR 16-17; VR i8; LS 42; PDS 12-13; CPS

16-17; TS 11-12.

Pigmentation. The base color of the body is yellow-brown in life.

The white tail has a black stripe through the central rays, and two

black oblique bars in each lobe. The top of the head, dorsum, and upper

sides are heavily spotted, but the belly is white. The spots on the

sides (one per scale) are arranged in nine or ten horizontal rows. The

sides have two white stripes devoid of spots that continue posteriorly

onto the tail. The dorsal fin is white with a large black distal blotch

on its first rays, and a row of black spots nearer base. The pectoral

and pelvic fins are whitish to clear. The anal fin is white with a

central black blotch.



























































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Distribution and Natural History

Range. The range is not well documented but it probably occurs in

most of the Andes in Venezuela and Colombia. There are reports of this

species from the Guyana Shield in Venezuela, but I have not seen speci-

mens. The form there may represent a different species.

Arure distribution. Map: fig. 8. It has been found only in the

western portion of the Apure drainage, usually in the Andean foothills.

Habitat. It lives in clear, clean, fast-flowing mountain streams.

Juveniles have been taken at Bruzual in the quiet edges of the Apure

River from aquatic vegetation. They perhaps were washed out of the

mountains, or the reproductive cycle might include a downstream phase

with later upstream migration.

Abundance. UNCOMMON.

Number of specimens examined. 49 from 16 collections.

Food. OMNIVORE. It feeds on both insects and vegetable matter. I

observed several individuals biting at rocks in the clear waters of the

upper Rio Caparo, presumably selecting items from the epibenthos.

Reproduction. Probable strategy: r2.

Importance. It has great potential as an ornamental.

Leporinus cf maculatus MUller & Troschel 1844

Spotted Leporinus Mije Pintado or Cabeza de Manteco

Fig. 9. Map: fig. 10. Couplet 10a.

Generic synonymy

Leporinus Spix in Agassiz 1829:65 (type species: Leporinus fasciata

Agassiz, by monotypy).

Hypomasticus Borodin 1929:287 (type species: Leporinus mormvrops

Steindachner 1875, designated by Fowler 1950:228).






































Figure 10. Leporinus cf maculatus.







Specific synonymy

Leporinus maculatus Muller & Troschel 1844:86 (type locality: Guyana);

1845:11 (rivers of Guyana); Eigenmann 1912a:305 (redescription);

Fowler 1950:237 (synonymy); Gdry 1977:166 (key, discussion of many-

spotted Leporinus).

Leporinus meqalepis Gunther 1863:443 (type locality: Essequibo River,

Guyana).

Leporinus marcqravii Lutken 1874b:130 (type locality: Rio Velhas and

tributaries).

Comments. The counts for Apure drainage specimens are consistently

higher than those given by Eigenmann (1912) for specimens from Guyana,

either because of a more inclusive counting method, or because different

species are involved. Gery (1977) discussed the complex taxonomic

problems of the many-spotted Leporinus species. He stated that in

current usage both aquarists and ichthyologists have confused L. pelle-

grini with L. maculatus, and that the name L. maculatus has been applied

to at least two very different species. I follow him in using L. macu-

latus for the species with a ventral mouth. He placed this species in

the subgenus Hypomasticus.

Etymology. LEPO = rabbit, RINUS = snout; MACULATUS = spotted.

Description

Illustrations. Fig. 9; Eigenmann 1912:pl. 43, fig. 2; Axelrod et

al. 1971:F377.00; Gery 1977:166; RomAn 1985:141.

Diagnosis. The pigmentation pattern is distinctive (fig. 9).

This is the only Leporinus with five or more large spots on the sides.

The ventral mouth is also unique.

Size. It grows to at least 200 mm SL.







Morphology. The head length is about equal to the greatest body
depth. The interorbital width is less than the snout length.

Counts. DR iilO; AR ii9; PR i14-i16; VR i8; CPS 16; LS 38-40; TS
11-12 5-6 above, and 5 below lateral line.

Measurements. HL = 22% SL; GBD = 27-33% SL (Eigenmann 1912 for

Guyanan specimens). In Apure specimens, GBD and HL = 24-26% SL; EYE =

50-66% HL, 10 = 43-55% HL, and SNT = 20-24% HL.

Pigmentation. The body is marked with several large ovate black

spots along the lateral midline, and on the upper and lower sides This

is a pattern similar to that of most juvenile anostomids, but in this

case it has been retained in the adult.

Distribution and Natural History

Range. It occurs in the Guianas and in the Orinoco Basin.

Apure distribution. Map: fig. 10. It is known only from the Agua-
ro-Guariquito system in the easternmost portion of the Apure drainage.

Habitat. It occurs in clear and blackwater creeks of the upper
Aguaro River system, in sandy bottomed savanna streams with abundant

aquatic vegetation.

Abundance. RARE.

Number of specimens examined. 6 from 4 collections.

Food. HERBIVORE. It is probably mainly herbivorous, though occa-

sionally aquatic insects may be included in the diet.

Reproduction. Probable strategy: r2. It is probably an egg scatterer

that synchronizes its annual reproductive effort with the beginning of the

rainy season. Axelrod et al. (1971) reported that this species spawned in

aquaria, scattering eggs all over, and then eating them if not removed.

Importance. Ornamental.





















































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Leporinus friderici (Bloch) 1794

Leporinus Mije

Fig. 11. Map: fig. 12. Couplet 11a.

Specific synonymy

Salmo friderici Bloch 1794:94, pi. 378 (type locality: Surinam).

Leporinus friderici Muller & Troschel 1844:87; 1845:11; Eigenmann &

Allen 1942:305 (Venezuela); Fowler:1950:233 (synonymy).

Leporinus fridericii Kner 1859:170 (misspelling).

Leporinus frederici Valenciennes in Cuvier & Valenciennes 1849:25

(misspelling).

Leporinus fradericii Goeldi 1898:482 (misspelling).

Curimatus frederici Perugia 1891:641.

Curimatus acutidens Valenciennes 1847:9, pl. 8, figs 1-la (type locali-

ty: South America)

Leporinus megalepis (non Gunther 1863) Gunther 1864:307 (part).

Leporinus leschenaultii Valenciennes in Cuvier & Valenciennes 1849:30,

pl. 635 (type locality: Mana); Peters 1877:472 (Calabozo, Venezuela);

Eigenmann & Eigenmann 1891:51 (Calabozo, Venezuela); Pellegrin

1899:157 (Apure River, Venezuela).

Comments. Identification of species in the L. friderici group is

difficult, see Gdry (1977) and Garavello (1988) for a brief outline of

the problem. Apure specimens resemble L. subniqer Fowler 1943 from

Florencia, Colombia in the Andean piedmont, and both of these seem

quite similar to L. bahiensis Steindachner 1875 from Brazil.

Etymology. FRIDERICI = probably named for the German monarch

Frederick the Great (1712-1786).





































Figure 11. Leporinus friderici.







Description

Illustrations. Fig. 11; Eigenmann 1912:pl. 63 fig. 4; Axelrod et

al. 1971:F-376.00; Gdry 1977:168.

Diagnosis. The pigmentation pattern is distinctive (fig. 11). Adults

usually have only two large spots on the sides. This species is very simi-

lar to Leporinus sp. "aguaro," but that form usually has three large spots

on the sides, and has a relatively larger eye (the eye diameter is more than

half of the interorbital width vs less than half in L. friderici. Faded

specimens of L. friderici (without spots) are similar to "Leporinus sp.,"

but the latter has much wider lips, and more lateral-line scales (42-44 vs

38-40). L. boehlkei Garavello 1988 has fewer lateral-line scales (35-36),

and fewer circumpeduncular scales (12 vs 16).

Size. It reaches at least 350 mm SL.

Morphology. This is a very robust, deep-bodied Leporinus with a

stocky appearance. The mouth is terminal.

Counts. DR iilO; AR ii9; PR i14-i16; VR i8; LS 38-40; PDS 9-12;

CPS 16; TS 11-12; teeth 3-3 on premaxilla, middle incisors bifid, the

others strangely curved; 3-4 teeth on dentary, the last one tiny and

next to base of last big tooth.

Measurements. GBD 32-36% SL.

Pigmentation. The dorsum is grayish, and crossed by about 12-15

faint vertical bars and the ventrum is light tan. The sides are brown,

with at least two large, rounded black spots, the first spot under

dorsal fin base, the second just anterior to the adipose fin. Sometimes

there is an additional spot at the base of the caudal fin. The fins,

especially the anal, are dusky and heavily pigmented on the membranes.

The adipose fin is often edged in black.




























































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Distribution and Natural History

Range. It occurs in the Amazon and Orinoco basins, and the

Guianas.

Aoure distribution. Map: fig. 12. It is common throughout the

piedmont and llanos.

Habitat. It lives in a wide variety of streams and rivers from

both white and blackwater habitats.

Abundance. COMMON.

Number of specimens examined. 230 from 64 collections.

Food. OMNIVORE. It feeds mostly on aquatic plants, but seeds and

carrion (fish flesh) are also included in its diet (K. Winemiller pers.

com.).

Reproduction. Probable strategy: r2. This species migrates down-

stream shortly after the first rains of the season. Spawning probably

takes place in midriver, in a fashion similar to Prochilodus mariae.

Migrations. This fish is known to accompany Prochilodus mariae on

annual migrations from the lowland floodplain habitats upstream to

piedmont and montane streams at the beginning of the dry season, and

thence back downstream when the seasonal rains begin.

Importance. It is of minor importance as a commercial species.


Leporinus sp.

Fatlip Leporinus Mije

Fig. 13. Map fig. 14. Couplet 9a.

Comments. This may be a new species. Its plain coloration and

meristic characters don't agree well with any described species.





































Figure 13. Leporinus sp.







Description

Illustrations. Fig. 13.

Diagnosis. This fish is quite plain, usually brown when adult,

with a small black spot at the base of the tail (fig. 13). The lip is

much thicker and more gently curved than in the similar L. friderici.

It has a more slender body as well. The lateral-line scale count of 42

to 44 is higher than for most other Apure drainage Leporinus species, in

which the number usually does not exceed 40.

Size. It reaches at least 250 mm SL.

Counts. DR iilO; AR ii9; PR i14-i18; VR i8; LS 42-44; PDS 12-13;

CPS 16; TS 13-14.

Measurements. GBD 26-30% SL in specimens above 90 mm SL.

Pigmentation. The body in adults is plain brown with a small spot

at the base of the caudal fin. Smaller specimens may have two or three

spots on the sides.

Distribution and Natural History

Range. It is known from the Orinoco Basin.

Apure distribution. Map: fig. 14. It occurs throughout the pied-

mont and llanos.

Habitat. It lives in muddy (whitewater) streams and rivers.

Abundance. COMMON.

Number of specimens examined. 81 from 25 collections.

Food. OMNIVORE. It is probably mostly vegetarian, but undoubt-

edly includes some aquatic invertebrates in its diet.

Reproduction. Probable strategy: r2.

Migrations. It makes annual migration similar to those of

Prochilodus mariae, and often accompanies that species during the


































































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the onset of the dry season in October or November).

Importance. It is of only minor commercial importance.


Leporinus sp. "aguaro"

Leporinus Mije

Fig. 15. Map fig. 16. Couplet 11b.

Comments. This species is similar to the species I have identified

as L. friderici, and could turn out to be the "real" L. friderici. If

that is the case, the species I have identified as L. friderici is

probably new. The original descriptions don't provide adequate informa-

tion to make a certain determination. L. friderici was described from

Surinam, presumably from blackwater rivers typical of the Guyana Shield

and coastal drainages. Leporinus sp. "aguaro," is apparently restricted

to similar habitats in the Apure drainage.

Description

Illustrations. Fig. 15.

Diagnosis. This species can be distinguished by pigmentation

pattern (fig. 15), which consists of three to four large spots along the

lateral midline plus a faint row of smaller spots above them on the

upper sides. It has fewer lateral scales (39 vs 42-44) than Leporinus

sp., and a relatively larger eye (the eye diameter greater than half of

the interorbital width) than L. friderici (less than half the interor-

bital width).

Size. It grows to at least 200 mm SL.

Morphology. The snout length is about equal to the interorbital


width.






































Figure 15. Leporinus sp. "aguaro".







Counts. DR iilO; AR ii9; PR i15-i16; VR i8; LS 37-39; PDS 10-12;

CPS 16; TS 11-12, with 5-6 scales above and five below the lateral

line.

Measurements. GBD 29-32% SL; HL 28-31% SL; EYE in HL 22-34%, in

SNT 53-96%, in IO 54-86% (the large variation in eye diameter is due to

allometry, juveniles have relatively larger eyes).

Pigmentation. The body is brown, darkest on the dorsum and

becomes gradually whiter towards the belly. The sides are marked with

three or four large black rounded spots, the first under the posterior

dorsal-fin base, the second just anterior to the adipose fin, the third

under the adipose fin, and the fourth on the caudal peduncle. Another

series of seven smaller spots is situated above these on the upper

sides. Each scale has a dark spot on its margin, resulting in up to 10

horizontal rows of dots; in some specimens the dark pigment completely

outlines each scale, forming a net-like pattern.

Distribution and Natural History

Range. It occurs in the Orinoco Basin.

Apure distribution. Map: fig. 16. It is known only from the

Aguaro River system.

Habitat. It occurs in blackwater streams and rivers.

Abundance. RARE.

Number of specimens examined. 3 from 3 collections.

Food. OMNIVORE. It is probably mostly herbivorous.

Reproduction. Probable strategy: r2.

Migrations. They are probable, but not documented.

Importance. It is potentially valuable as an ornamental.

















































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Leporinus cf striatus Kner 1859

Striped Leporinus Mije Rayado

Fig. 17. Map fig. 18. Couplet 8a.

Specific Synonymy

Leporinus striatus Kner 1859:171 pl. 8, fig. 18 (type locality:

Orissanga, Rio Parana and Caicara Mato Grosso, Brazil); Pellegrin

1899:157 (Apure River, Venezuela); Gdry 1977:170 (key).

Ledorinus (error) striatus Bertoni 1939:54 (Paraguay).

Salmo tiririca Natterer in Kner 1859:172 (?based on same type as

L. striatus Kner).

Comments. Since L. striatus was described from southern Brazil, it is

doubtful that the same species is present in the Apure drainage. Fowler's

illustration (1950) depicts a fish with only two stripes on the side. I

have examined the holotype (FMNH 53366) of the similar L. arcus Eigenmann

1912, which was described from British Guiana, and which would perhaps be

more likely to occur in Venezuela. It is, however, a different-looking fish

with only four stripes on either side (vs five in Apure specimens). In

addition the dorsum in the L. arcus holotype is uniformly dark, and though

the pigment may have obscured a stripe that may have originally been

present, none is shown in the figure of the holotype (Eigenmann 1912:pl. 62,

fig. 3). The holotype has 36 lateral-line scales (vs 38 in Apure specimens)

and ten transverse scales (vs 12). Finally, specimens of the type series of

L. arcus greatly exceed the maximum recorded size for L. striatus. These

data strongly suggest that the Apure specimens are not L. arcus. I suspect

that the Apure drainage form is undescribed, but this cannot be finally

resolved until it can be compared with fresh material from the type locali-

ties of L. arcus and L. striatus.






































Figure 17. Leporinus cf striatus






Etymology. STRIATUS = striped.

Description

Illustrations. Fig. 17; Axelrod et al. 1971:F-378.00; RomAn

1983:99.

Diagnosis. The color pattern of black stripes over a yellowish

background (fig. 17) is unique for Apure drainage anostomids. In this

regard it is superficially similar to Anostomus ternetzi, but that

species has a superior mouth and is much more slender and elongate.

Size. It is seldom found over 100 mm SL, but can reach 175 mm.

Morphology. This is a robust, stocky fish. The horizontal diame-

ter of the orbit is longer than the snout length, but slightly less than

the interorbital width. The mouth is subterminal.

Counts. DR iilO; AR ii8; PR i14; VR i8; LS 38; PDS 10; CPS 16; TS 12;

teeth 3-3, 3-3 or 4-4 (if four the last very small), the teeth are curved

incisors with brown tips, not truly cuspid but with irregular margins. The

center of the roof of the mouth has a bulbous papillose projection.

Measurements. GBD about 29% SL; HL 36% SL; EYE 36% HL. IO 39% HL.

Pigmentation. Juveniles up to about 40 mm SL show vertical

banding instead of the typical adult pattern of horizontal light and

dark stripes. They also have a jet-black adipose fin with a light

center, a dark crescent along base of tail with darker dot at midpoint,

and a black anal fin. Juveniles also lack pigment on the fontanel and

have about three vertical stripes anterior to the dorsal fin. At 19 mm

SL one juvenile had only vertical barring, but another specimen of 37

mm SL had the beginnings of horizontal stripes.

Adults have a black line along the dorsal midline of the body in

front of the dorsal fin, but the dorsal midline of the head has a white




77

stripe. They have five additional dark stripes on either side, the

first of which extends from the occiput along the uppermost sides and

back to the adipose fin. The second extends from the snout, back above

the eye to the uppermost caudal-fin base. A third extends from the

snout through the eye across the opercle and back along the midside to

midtail. The fourth extends from the pectoral-fin base (which is dark

dorsally near its base) back to the anal fin and onto the lower caudal

peduncle. The fifth stripe is faint and extends from the lower pectoral-fin

base to the pelvic-fin base. The adipose and anal fins are black, the other

fins white, tan, or transparent.

Distribution and Natural History

Underwater observations confirm that this species usually travels

in schools, as do most Leporinus. However, since they occur over rocky

substrates where seines are easily avoided, most of our collections are

of very few specimens.

Range. It has been reported from the Orinoco, Amazon and Parana

basins.

Apure distribution. Map: fig. 18. It is most common in the Andean

piedmont and streams in the upper llanos.

Habitat. L. striatus is most commonly found in clear streams and

rivers, with fast currents and rocky substrates.

Abundance. COMMON.

Number of specimens examined. 109 from 35 collections.

Food. OMNIVORE. It is probably mostly herbivorous.

Reproduction. Probable strategy: r2.

Importance. Ornamental.

























































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Leporinus yophorus Eigenmann 1922

Banded Leporinus Mije Rayada

Fig. 19. Map fig. 20. Couplet 8a.

Specific synonymy.

Leporinus yophorus Eigenmann 1922:233 (type locality: Barrig6n,

Colombia, upper Rio Meta)

?Leporinus affinis Pellegrin 1899:157 (Apure River, Venez.).

Types: Holotype: CAS 61680 (formerly IU 15025).

Comments. There are many names available for vertically banded Lepori-

nus species. Most often they are called L. fasciatus, but L. latofasciatus

and L. pearsoni are other possibilities for Venezuelan specimens. The Apure

form agrees almost exactly with Eigenmann's (1922) original description of

L. vophorus. Since both the habitat and drainage coincide, I feel reasona-

bly confident about this identification. It is also possible that L. vopho-

rus could prove to be a junior synonym of one of the older names such as

Leporinus affinis GUnther 1864, which was described from Para, Brazil, and

was cited by Pellegrin (1899) from the Apure River. However, that species,

which has nine vertical bars according to Gdry (1977), is probably not

present in the Orinoco Basin.

Etymology. Y = the letter "Y" refers to the Y-shaped bar on the

side, OPHORUS = bearer of.

Description

Illustrations. Fig. 19; Eigenmann 1922:317 pl. 20, fig 4.

Diagnosis. The color pattern (fig. 19) is distinctive since this

is the only Apure drainage Leporinus with bold vertical bars.

Size. It grows to about 180 mm SL






































Figure 19. Leporinus yoDhorus.




82

Morphology. This is an elongate, slender Leporinus with a terminal

mouth.

Counts. DR iilO; AR ii9; PR i15-i16; VR i9; LS 42-45; PDS 14-16;

CPS 16; TS 12, 6 above, 5 below lateral line.

Measurements. Eigenmann (1922) gave the following measurements for

the type: Head 5.0 in SL, depth 4.66, eye 2 in snout, 4.5 in the head,

2.0 in the interorbital; isthmus 3.5 in head; depth of caudal peduncle

2.4 in head. Apure specimens: GBD 23% (adults) to 29% (juveniles) SL;

Eye 18% (adults) to 29% (juveniles) HL.

Pigmentation. The body is yellowish with seven wide vertical bars.

The second bar is divided at the level of the lateral line to form a "Y"

that extends dorsally.

Distribution and Natural History

Range. It occurs in the Orinoco Basin.

Apure distribution. Map: fig. 20. It is known only from four

localities, three from within or near the Apure River itself, and one

from the Tucupido River in the piedmont.

Habitat. There are insufficient numbers of collections to

permit a thorough characterization of this species' habitat.

The one adult captured was collected from a site in the Andean piedmont

in a rapidly flowing, rocky river. The juvenile specimens were taken

from near shore in muddy-bottomed side pools of the Apure River near

Bruzual, amidst aquatic vegetation and submerged grasses. Thus, it

seems that llaneran whitewater rivers are this species habitat.

Abundance. UNCOMMON, but it is probably difficult to capture.

Number of specimens examined. 84 from 11 collections.

Food. OMNIVORE. It is probably mostly herbivorous.





























































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Importance. Ornamental.


Pseudanos gracilis (Kner) 1859

Banded Headstander Cabezibajo Rayada

Fig. 21. Map fig. 22. Couplet 4b.

Generic synonymy

Pseudanos Winterbottom 1980:24 (type species: Schizodon trimaculatus

Kner 1859:161, by original designation).

Specific synonymy

Schizodon gracilis Kner 1859:160 (type locality: Rio Guapor6, Brazil).

Anostomus gracilis Myers 1950:184; Kn6ppel 1972:268 (diet); Mago L.

1970:75.

Pseudanos qracilis Winterbottom 1980:24 (redescription).

Types. Holotype: NMW 57-119.

Description

Illustrations. Fig. 21; Winterbottom 1980:83 fig. 20.

Diagnosis. The minute, superior mouth distinguishes this species

from all Leporinus species. The pigmentation pattern (fig. 21) is also

characteristic, and useful to distinguish it from P. qracilis, and

Anostomus ternetzi.

Size. It grows to 160 mm SL, but most individuals are smaller.

Morphology. The body is fusiform but somewhat compressed.

Counts. DR iiil0; AR iii8; PR i13-i16; VR i8; LS 43-47; PDS 11-15;

CPS 16; TS 10, teeth 4-4 in both jaws (each with 2 to 4 cusps, though

these can wear down, and become less conspicuous).

Measurements. GBD 18.3-25.4% SL







































Figure 21. Pseudanos gracilis.






























































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Pigmentation. The pigmentation pattern varies in preserved material,

but the dorsum never has cross bars. The body has up to 11 thin horizontal

stripes formed by rows of dots (one per scale). A median predorsal stripe

is also present. The midlateral sides are marked with a dark stripe or with

series of up to four large rounded spots.

Etvmology. PSEUD = false, ANOS = the first four letters of Anostomus,

a very similar genus; GRACILIS = slender.

Distribution and Natural History

Range. It occurs in the Amazon and Orinoco basins.

ADure distribution. Map: fig. 22. It has been found only in the

Aguaro River system. Interestingly, the distribution of this species seems

to complement that of P. irinae, which is absent from the Aguaro systems but

present in suitable blackwater habitats of northern Apure and Barinas.

Habitat. It is restricted to blackwater streams with abundant aquatic

vegetation.

Abundance. RARE.

Number of specimens examined. 8 from 5 collections.

Food. OMNIVORE: It feeds on plant remains, fungi, algae, detritus,

sand and terrestrial insects (Winterbottom 1980).

Reproduction. Probable strategy: rl.

Importance. Ornamental.


Pseudanos irinae Winterbottom 1980

Three spotted Headstander Cabezibajo de Tres Puntos

Fig. 23. Map fig. 24. Couplet 3a.

Specific synonymy

Pseudanos irinae Winterbottom 1980:27 (type locality: Orinoco River

system, Cano de Quiribana where it empties into the Orinoco).






































Figure 23. Pseudanos irinae.







Anostomus trimaculatus (non Kner 1859) Eigenmann 1912:295 (Essequibo

River; Myers 1950:184 (upper Orinoco); Ramirez 1957:157 (Venez.);

Mago L. 1970:75 (Venez.).

Types. Holotype: CAS 58809. Paratypes: deposited at AMNH, BMNH,

CAS, FMNH (3) (Winterbottom 1980), catalog numbers not given.

Etymology. IRINAE = named for the wife of Dr. R. Winterbottom,

Irina.

Description

Illustrations. Fig. 23; Axelrod et al. 1971:F-41.00 (identified as

Anostomus trimaculatus); Winterbottom 1980:83, fig. 21.

Diagnosis. The pigmentation pattern is distinctive (fig. 23).

Size. It grows to about 100 mm SL.

Morphology. The body is fusiform and somewhat compressed.

Counts. DR 13-14; AR iii7-iii8; PR i13-i16; VR i7-i8; LS 41-45;

CPS 16.

Measurements. GBD 23-29% SL.

Pigmentation. This fish is yellow-brown, paler below, with the dorsum

crossed with irregular, thin vertical bars, and two to four dark spots or

blotches on the sides. The first of these spots covers scales three to five

of the lateral-line series and is situated partly beneath the lateral line),

the other spots cover scales 16-19, 29-30, and 41-46. The first and third

spots are often faint and may be absent. The area around each spot is

lighter.

Distribution and Natural History

Range. It occurs in the Orinoco and Essequibo basins, of Colombia,

Venezuela and Guyana.






























































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Apure distribution. Map: fig. 24. It is so far known only from the

SuripA River in Barinas, and the Guaritico system of northern Apure state.

Habitat. It is restricted to black or clearwater streams in the

savannas of the low llanos. and is usually found in aquatic vegetation.

Abundance. UNCOMMON.

Number of specimens examined. 17 from 6 collections.

Food. OMNIVORE. The diet of this species is probably similar to that

of the similar, preceding species which feeds on plant remains, fungi,

algae, detritus, and insects.

Reproduction. Probable strategy: rl.

Importance. Ornamental.


Schizodon isoqnathus Kner 1859

Boquimi, Coti, Pijotero Schizodon

Fig. 25. Map: fig. 26. Couplet 5a.

Generic synonymy

Schizodon Agassiz 1829:66 (type species: Curimatus fasciatus Agassiz, by

monotypy).

Specific synonymy

Schizodon isoqnathus Kner 1859:163 pl. 6 (not pl. 7 as stated in

the text; type locality: Rio Cujaba).

Anostomus isoqnathus Peters 1877:472 (San Fernando de Apure, Venez.).

Comments. Recent investigations by biologist Maria Esther Antonio

of the Universidad Central de Caracas indicate that this species is

distinct from the Amazonian S. isoqnathus, and perhaps new.

Etymology. SCHIZ = divided, ODON = teeth; ISO = even, equal,

GNATHUS = jaws.