New collections of annual Cyprinodonts from the Paraguayan Chaco, with descriptions of four new species.

Jean H. Huber* (working translation into English by Dan Fromm)

* Museum national d'Histoire naturelle, Laboratoire d'Ichtyologie, 43 rue Cuvier, 75231 PARIS Cedex 05, France.

Abstract : Four collecting trips undertaken from 1992 to 1994 by two families of enthusiastic aquarists, one from North America (Fromm) and the other from Holland (Van den Berg), have considerably improved our knowledge of the South American Cyprinodonts of Paraguay, and especially from the Paraguayan Chaco : 39 new collecting localities of annual species are reported, and 4 new species, all annual, described : Cynolebias patriciae n.sp., C. vandenbergi n.sp., C. monstrosus n.sp., and Trigonectes aplocheiloides n.sp. Another annual species, described by Costa (1990a) under the name Plesiolebias bitteri, from a commercial import without a precise type locality, has been rediscovered in eight places : it is redefined and a locality of origin is assigned. The systematics of Cynolebias and allied genera are discussed, and three conditional changes proposed: Plesiolebias should be downgraded to subgeneric rank, Simpsonichthys could be redefined as a subgenus of Cynolebias, and the typical subgenus Cynolebias s.s. should be restricted to the very large species which prey on smaller congeners. Finally three other groups, for the time being nameless, could be defined.

Paraguay : A poorly-explored country particularly rich in good biotopes for annual Cyprinodonts

Until the collections reported on here, Paraguay's Rivulins were not well known; only six species had been reported, and infrequently :

Rivulus punctatus, the first and best known, was described by Boulenger (1895) from specimens brought from Colonia Risso (22.35S, 57.83W - note that in all our papers latitude and longitude are stated in degrees and hundredths, not in degrees and minutes) in northern Paraguay on the Brazilian border. It has since been collected from many localities, of which more than 20 are in Paraguay (Huber, 1992). However, R. punctatus is still poorly known; the life colors of the type population, so important for Cyprinodont systematics, have never been recorded. In fact, the specimens recently collected, far from the type locality, have been studied preserved. It is one of the more slender and small Rivulus (max. TL 35 mm), characterized by red chevrons on the flanks and a white or yellow marginal band around males' tails, a temporary black longitudinal band along the lateral scales, and marked sexual dichromatism.

The second species, an annual, has been identified as Pterolebias longipinnis. This identification, which we find dubious, in as much as the species, still unknown alive, has been described by Garman (1895) from Santarem (2.42 S; 54.73 W), in central Northern Brasil of the lower Amazon, i.e. at about 2000 km of the paraguayan localities; although the caryotype of Pterolebias longipinnis s.l. seems variable (Scheel, pers. comm.) we feel preferable not to modify provisionally this identification until further live material is made available and to name this fish P. sp. aff. longipinnis. Anyway, another name, to-day a junior synonym, is available, P. luelingi (Meinken, 1969) described from Rio Chapare in Bolivia (16.83 S; 65.17 W), a much less distant locality (600 km, anyhow!).

The third, C. chacoensis, also annual, was recently described by Amato (1986) in a publication bearing primarily on the Uruguayan fauna. Its life colors, unknown then, are described and illustrated here for the first time from specimens collected in the high Chaco near the type locality. Its coloration is striking and the fish was quickly identified thanks to Amato's figures.

The fourth and fifth, N. paraguayensis (Eigenmann and Kennedy, 1903) and N. ornatipinnis Myers, 1935, both annual, belong to the genus Neofundulus Myers (1924). Their status has been so confused that, on the one hand some authors have synonymized them, while on the other Parenti (1981), in her cladistic revision of the Cyprinodonts, used the two species as the types of two different genera, one unnamed. The type localities of N. paraguayensis and N. ornatipinnis have respectively the following geographical coordinates: 24.82S; 54.06W and 23.42 S; 58.32 W (Huber, 1994), each other distant by 170 kms. Despite this relative proximity and similar color patterns, the brazilian ichthyologist Wilson Costa (1988, 1992) has kept valid the two taxa, after having reviewed the genus and described 2 then 1 new brasilian species.

The sixth and last, Plesiolebias bitteri, also an then nual, was recently described by Costa (1990a) from specimens commercially imported into Germany from Paraguay, without information about where in Paraguay the specimens had been collected. The killie fancier Friedrich Bitter 'discovered' it in a wholesale establishment, bred it, and distributed it widely. We have been able to study its color pattern thanks to a photograph kindly provided by R. Wildekamp.

R. punctatus excepted, each of these fishes has been known from only a few collecting localities. This is absurdly few for a country as relatively small and thinly populated (407,000 square km, about 10 persons per square km), as Paraguay.

Paraguay is a country of South America which does not enjoy links with the sea; its hydrography is very simple as much as nearly all waters are tributaries to the Rio Paraguay, a large river which flows from North to South in the middle of the country and merges with the Rio Parana at the extreme south of the country; it crosses then northern Argentina, to dive into the Atlantic ocean by forming a gignatic arm named Rio de la Plata. Countrysides and biotpes of this hydrographic basin are varied: forested savannah, up to semi-desertic, with many temporary bodies of water building marshes and stagnant pools; but also marshes of the neighboring brazilian Pantanal.

It is to the credit of the American amateurs Daniel and Patricia Fromm that they had the insight and courage to be the first aquarists to mount a systematic collecting trip to this country, which they believed rich in annual species allied to the genus Cynolebias. In fact, until the 1980s, it was firmly believed that the distribution of annual Rivulins in South America was restricted to coastal regions of Venezuela, Brazil, Uruguay, and Argentina. It was only at the end of the decade that numerous collections from the interior plateau of Brazil, thanks to LaCorte, Campello-Brasil, and Costa, proved the opposite.

With the Fromms' new collections, in October,1992 and May and June, 1993, and those of the Dutch collector Leen Van den Berg and his son Arjen, in July, 1993 and March 1994, one region of Paraguay, the high Chaco, has been well worked over. Some sites have been visited twice at a one year interval. In addition, the Fromms made a single collection of annuals not far from Asuncion (cf. Table 1, the list of sites, and figure 1, a map of the high Chaco). Thanks to their initiatives, many of these fishes have been brought back alive and reared for the first time, and their ecology is better understood. Specimens have been deposited in museums in quantities sufficient to make study possible. We thank the collectors for having given specimens to museums. We thank them also for the valuable advice that they have given us and for having shared their aquaristic experiences with us. We note finally that all of the specimens donated by Jan Willem Hoetmer had been held for 2 to 4 months in the aquarium.

Ecology of the Upper Chaco

The entire region northwest of the Rio Paraguay is called the Chaco, from the name of the river which drains it, and is not to be confused with Chaco province of Argentina. This region, a plain with altitude between 100 and 180 meters, could be divided into three climatic zones, the low, middle, and high Chaco, which merge into each other. The low Chaco is a band of marshes 200-300 km wide whose eastern limit is the Rio Paraguay; its characteristic flora includes aquatic plants in the genera Pistia and Echinodorus, many palms, and some thorn bushes. It merges gradually into the middle Chaco, of similar width but drier. The middle Chaco's flora contains more and larger thorn bushes, some cacti, and the famous Paraguayan Bottle Tree. The transition to the high Chaco is marked by terrain rising slowly towards the Andes' foothills; cacti become increasingly abundant and the environment increasingly dry. At its western limit, the high Chaco is arid, without vegetation, and has sand dunes.

The Chaco's subsoil is an impermeable clay which favors the formation of temporary pools. Surface water is normally sweet, while spring water can be saline. The presence of salt lakes in the middle and high Chaco reflects this.

During the rainy season, from October to March, the Chaco floods severely and fishes normally found in the Rio Paraguay are taken in its tributaries as far as 500 km upstream. The association of rainy and dry seasons with clayey subsoils allows temporary biotopes suitable for annual Rivulins. The best time for collecting them, in principle, is the months of March through June, one or two months after the end of the rainy season. However, as the rains of 1992-3 failed most favorable biotopes dried up prematurely in 1993.

Biotopes of annual Cyprinodonts in Paraguay are like those found throughout shrubby and grassy savannas in South America, and also in east Africa for the genus Nothobranchius. They comprise pools and lakes (lagoons), swamps, canals and temporary roadside ditches, flooded meadows, and flooded areas near rivers. It is in these last that the non-Cyprinodont fauna is richest, with traditional predators like Crenicichla sp., Piranhas, Hoplias, Erythrinus, as well as small cichlids, e.g., Apistogramma borelli, and small characoids such as Hemigrammus and Aphyocharax.

In March 1994 the water (pers. comm., Leen Van de Berg and Jan Willem Hoetmer) was almost always shallow (15-50 cm); rather turbid to muddy, rarely clear; bottoms were clayey, rarely with humus; aquatic and emerse plants and filamentous algae were common; pH was neutral to alkaline (6.2 < pH < 7.5), and, more important, unlike forest water, the conductivity was relatively high, usually 100-200 µS, but as high as 800µS; water temperatures ranged from 27°C in morning and late afternoon to 36°C at midday. The Fromms' measurements in October and June agree with these, but with lower midday water temperatures, 23-25°C. In addition, they frequently report the presence of floating plants in the genera Lemna and Eichhornia, as well as Echinodorus and Pistia.

Sympatry (syntopy, in the restricted sense of some anglophone authors) and allopatric vicariance, which are the major elements of speciation in Rivulins (Huber, 1992) and probably also in the other Cyprinodonts, are equally confirmed here. At three sites as many as four annual species have been collected together; this is many, considering how homogenous the biotopes are, the differences in niche, behavior, food, (… ) that having so many species together requires, and given the similarity (not as much, obviously, as the non-annual species) of most of the females of the different species. In addition, despite the narrow distribution of collecting sites, it appears that there are groups of cryptic species of the same superspecies in Paraguay, Argentina, Uruguay, and the extreme south of Brazil. For example, the three isomorphic species C. elongatus, C. prognathus, and C. monstrosus, newly described here, form a monophyletic group.

Study of the annual Rivulins of the genus Cynolebias

Cynolebias patriciae, new species (fig 2).

Holotype. ANSP (1) 170424, male, 24.3 mm SL and 32 mm TL.

Paraguay, Presidente Hayes department, ditch along the road to Clorinda, approximately 500m south of Rio Negro (Station DF 93-28). 25.25S, 57.67W. Dan and Pat Fromm, June 11, 1993.

Paratypes. ANSP 170424B, 1 male examined, 24.0 mm SL and 30.6 TL and 10 individuals, 9 males and 1 female, of which 4 were transferred to MNHNP (abbreviations of institutional names explained at the end of this paper), number on request, and 2 to MACN, number on request. MNHN 1993-3620, 4 males and 1 female examined, all collected with the holotype.

Diagnosis :

Small relative to the average of the genus, resembling C. alexandri and affinis by its blue-green coloration, but distinguished when preserved by a rather less marked dichromatism, prominent anterior bars and by certain meristic data (males average A = 23-24 versus 21-23; LL=23-25 versus 25-26, and especially D/A = +2 to +4 versus -1 to -3); in addition, C. patriciae has a line of 8 - 12 neuromasts in place of a preopercular canal, and many others partially surround the eye, which is placed higher. The pectorals are long, reaching the fourth anal ray in the male (scarcely the first in alexandri and affinis) and the second in the female. Finally, a significant ( ?) element, the membrane between the rays of the vertical fins does not extend as far as their distal edge, the opposite of affinis, thus creating a ragged outline.

Life colors :

Male, female, and juveniles dissimilar (the inverse of the color in alcohol). Only juveniles have large dark gray bars on the flanks and dark grey flames (= streaks) the length of the unpaired fins, more intense distally, almost forming a marginal band on the anal. The adult male is particularly handsome, especially when courting : the flanks are then an intense metallic green; normally only the lower flanks and the preopercular spot are bright emerald green, and the unpaired fins are densely spotted with the same color, all on an brownish beige base without stripes. A dark marginal band is present on the pectorals, the caudal, and the anal. The eye is, in contrast, circled with a brilliant orange and crossed by the black bar common among Cynolebias. The female is spotted vertically with maroon blotches on a lighter base, some, behind the opercle, are more intense and almost black. In color, the female bears a strong resemblance to the other small Cynolebias of Argentina, Uruguay, and the extreme south of Brazil.

Comparison with males of C. alexandri and C. affinis :

· patriciae is easily separated from alexandri by the well marked striped pattern, in the latter made of regular brown bars; even though they are apparent only in the juvenile, broader and more distinct behind the opercle in the former.

· patriciae is distinguished from affinis (D. Fromm, pers. comm) by the disposition of spots on the flanks (vertically in the latter; posteriorly in a horizontal median line in the former), by the length of the lower part of the black eye bar (short in the latter; long, reaching the jaw, in the former).

Color in alcohol

The two sexes, with an intense vertical (not oblique as in affinis) bar from one side of the eye to the other, followed by a light zone, then a dark grey zone, on the preopercle; the flanks display 7 broad dark grey bars, sometimes divided in two, and between them six narrower light bars; often, and particularly in subadults and dominant individuals, the two to four first bars behind the opercle are very dark, contrariwise the following bars more grey, and they stand out strongly. The male is distinguished from the female by the presence of dark flamess along all of the rays and of clear spots on the unpaired fins, as well as by the variably black trimmed end of the dorsal and anal. In the female, each bar on the flanks is interuppted at least once.

Size, proportions and formulas

Males approximately 40 mm TL, females a little less, after rearing in the aquarium.

Morphological and meristic data of the holotype, of a paratype 170424B and of paratypes in MNHN (holotype male first, in bold face, then 5 males and one female; abbreviations are explained in Huber, 1992) are, after radiophotographic confirmation : D= 22, 23, 22, 23, 23, 24, 18; A= 25, 24, 26, 25, 23, 24, 20; D/A= +2, +3, +2, +2, +3, +2, +4; LL= 25, 25, 24, 23, 25, 25, 24; TRAV.= 10, 9, 9, 9, 9, 10, 10; CIR= 14, 15, 13, 14, 14, 14, 15; L.S. (in mm)= 24.3, 24.0, 23.2, 23.2, 22.9, 21.0, 17.0; L.T. (in % of L.S.)= 132%, 128%, 131%, 126%, 124%, 130%, 126%; P.D.= 54%, 57%, 58%, 57%, 51%, 50%, 66%; P.A.= 51%, 54%, 53%, 52%, 49%, 51%, 59%; P.V.= 45%, 46%, 46%, 46%, 45%, 46%, 53%; depth at the anal= 33%, 30%, 34%, 31%, 29%, 29%, 34%; head= 33%, 31%, 34%, 34%, 33%, 30%, 36%; interorbital width= 13%, 15%, 13%, 13%, 11%, 10%, 13%; diameter of the eye= 7%, 7%, 7%, 7%, 7%, 7%, 9%; vertebrae= 11+15; 11+14; 11+16; 11+15, 12+16, 12+15.

One notes, as in many Cynolebias, an important sexual dimorphism. Fewer dorsal and anal rays, these fins inserted further to the rear, and form of the body more squat, in the female. For example, here the female shows 4-6 fewer dorsal and anal rays, and a D/A displacement, it seems, a little greater : this translates into a more rearwards position (8 to 10% of SL) of these fins.


The species is annual, but the duration of incubation in dry peat is unknown, attempts to breed it having yielded nothing; it is peaceful, but males do not tolerate each other, and for the genus is easily maintained; aquaristic experience will be reported in detail in Fromm (in prep.), at the same time as the biotope.


The Rio Negro crosses the road from Asuncion to Clorinda and discharges, not far from the type locality, directly into the Rio Paraguay. The other stream of the same name in that vicinity is an affluent of the Rio Pilcomayo. The species is known only from the type locality, across the Rio Paraguay from Asunci•n, the capitol of Paraguay. As the site is near the border with Argentina, it is very probable that the fish also occurs in the north of that country.


By its green color and general conformation, C. patriciae is close to C. alexandri, described from Gualeguaychu (33.07S; 58.57W) in Argentina, nearly 900 km to the south, and to C. affinis, described from Arroyo Tres Cruces (32.32S, 55.77W), in Uruguay, approximately the same distance to the southeast. More generally, C. patriciae belongs to a group of small Cynolebias species whose rounded unpaired fins do not have long filaments, whose males have the same average ray counts for dorsal and for anal fins, whose dorsal in inserted in front of or directly above the anal's insertion, and which have a southern distribution, viz., affinis, alexandri, costai, cyaneus, gymnoventris, luteoflammulatus, nigripinnis and patriciae. Together they form a group remarkably homogenous and distinct from other Cynolebias and would deserve the allocation of a subgeneric name. Costa, the specialist in these fishes, will probably do this.

Etymology : The species is dedicated to Patricia Fromm, Cherry Hill, New Jersey, U.S.A., following the wishes of her husband, with whom she discovered it.

Cynolebias vandenbergi, new species (fig. 3; drawing from the radiophotography of a male ANSP 169800, on cover sheet).

Holotype. ZMA 121270, male, 61.0 mm SL and 74.3 mm TL Paraguay, Boqueron Department, near Fortin Toledo, (Station LV 93-2 = LV 94-22). 22.27 S; 60.54 W. Leen and Arjen Van den Berg, July 23 1993, collected; Jan Willem Hoetmer, deposited.

Paratypes. NRM 20231, UFRJ 3028, 1 pair each, NMW 92900, 1 pair; MNHN 1993-297, 3 individuals (Station LV 93-2), aquarium reared. Leen and Arjen Van den Berg, 1993 coll. and J. Huber dep. ANSP 169800, 4 males, of which 2 will be transferred to MNHNP (number on demand), from a roadside ditch 14.4 km from the Filadelfia airport on the road from Filadelfia to Teniente Montania (Station DF 92-114); ANSP 169801, 5 males (Station DF 92-107B); ANSP 169802, 10 males (Station DF 92-107); ANSP 169803, 6 males (Station DF 92-110); ANSP 169804, 5 males (Station DF 92-122); ANSP 169805, 14 females (Station DF 92-122); ANSP 169806, 4 females (Station DF 92-108); ANSP 169807, 3 females (Station DF 92-114); ANSP 169808, 5 females (Station DF 92-110); ANSP 169809, 4 males (Station DF 92-108); ANSP 169810, 7 females (Station DF 92-107B); ANSP 169811, 1 female (Station DF 92-110); MNHN 1993-3618, 4 females, taken from lot ANSP 169812 of 23 females collected 19.3 km from Mariscal Estigarribia on the Ruta TransChaco (Station DF 92-107); Dan Fromm, 10-13 October 1992, dep. ANSP 170425, 2 males (Station DF 93-21); ANSP 170426, 1 female (Station DF 93-12); Dan and Pat Fromm, 7 and 5 June 1993, dep.

ZMA 121272, 4 individuals (Station LV 94-22); ZMA 121276 and MHNG (1) 2571.72, respectively 4 and 3 individuals (Station LV 94-26); ZMA 121277, 4 males (Station LV 94-24); ZMA 121278, 3 females (Station LV 94-36); ZMA 121279, 2 males and 2 females (Station LV 94-36); ZMA 121282, 2 individuals (Station LV 94-34);

MNHN 1994-1107, UFRJ 3029 and FMNH (1) 105075, comprising 5, 6, and 3 individuals respectively (Station LV 94-30). Leen Van den Berg coll., 1994; Jan Willem Hoetmer dep.


Very deep-bodied and of average to large size relative to the average of the genus, resembling C. bellottii, but easily distinguished from it by a less marked sexual dichromatism, anterior bars darker than the posterior and by morphomeristic characteristics (for example more dorsal and anal rays, smaller D/A displacement); in addition, C. vandenbergi possesses a double series of cephalic neuromasts forming an extension of the preopercular line towards the snout as well as, in the male, much longer pectorals, reaching to the third ray of the anal; finally, C. vandenbergi does not have the white marginal band which surrounds the caudal of male bellottii; the adult males display regular and complete series of ctenoid spines on the flanks, as many as transverse series of scales, and on the 4-6 rows of scales at the base of the anal.

Life colors

The male and the female differ little. Both have the characteristic black bar which crosses the eye and, variably, some 15 vertical dark grey bars on a lighter base. In addition the male displays numerous little whitish yellow shining spots all over the flanks; the spots are also found on the dorsal and anal, near their bases on a rather dark base. These two fins are dark-edged, while the tail is uniformly dark grey. The female has at least one or two black spots behind the opercle, bright golden reflections on the upper flanks and some greyish flames on a transparent base in front of the dorsal and anal.

Colors in alcohol : very variable

Both sexes, with a variable black vertical bar, more intense below the eye, followed by a pale zone, then a dark grey zone, on the preopercle; the flanks bear 13 to 15 broad vertical dark grey bars, some of them, depending on the individual, more intense than others (rather high up on the flanks) or replaced by black spots (somewhat behind the opercle). In the male, the barred pattern is inconstant. Females' fins are unspotted; the male's fins are dark grey, with the pectorals and sometimes the dorsal and the anal edged in black, and clear spots near the bases of the latter two fins.

Size, proportions, and formulas

Males around 90 mm TL, females a little less, after rearing in the aquarium (the largest male, from lot MNHN 1993-297, measures 86.7 mm). Morphological and meristic data of 16 types examined, 6 males and 10 females ( ? ?) (holotype first and in bold face) are, after radiophotographic confirmation : D= 26, 25, 24, 23, 23, 28, 21, 18, 23, 21, 22, 22, 27, 24, 21, 21; A= 31, 30, 30, 26, 26, 31, 28, 26, 27, 24, 26, 26, 32, 26, 26, 26; D/A= +4, +4, +4, +3, +5, +4, +2, +5, +4, +2, +4, +4, +5, +4, +4, +5; LL= 30, 32, 31, 30, 32, 30, 30, 31, 31, 30, 30, 29, 30, 30, 31, 28; pDor= 24, 23, 19, 19, 19, 22, 21, 23, 22, 20, 22, 22, 17, 21, 19, 20; TRAV.= 16, 18, 17, 17, 16, 17, 16, 17, 17, 15, 16, 15, 16, 17, 17, 16; CIR= 20, 19, 21, 19, 18, 19, 20, 20, 19, 18, 18, 19, 19, 22, 21, 18; L.S. (in mm)= 61.0, 62.4, 61.5, 47.8, 50.4, 32.8, 53.0, 43.6, 43.1, 39.9, 36.1, 31.9, 37.8, 52.2, 45.8, 37.8; L.T. (in % of L.S.)= 122%, 121%, 120%, 121%, 121%, 127%, 122%, 124%, 123%, 130%, 129%, 121%, 122%, 125%, 124%, 125%; P.D.= 54%, 58%, 55%, 57%, 55%, 54%, 61%, 60%, 60%, 59%, 57%, 57%, 51%, 61%, 64%, 52%; P.A.= 46%, 46%, 47%, 49%, 45%, 55%, 58%, 55%, 53%, 56%, 53%, 49%, 49%, 56%, 56%, 48%; P.V.= 40%, 40%, 40%, 43%, 39%, 46%, 49%, 45%, 45%, 48%, 46%, 42%, 43%, 46%, 46%, 44%; depth at the anal= 41%, 42%, 41%, 41%, 38%, 37%, 42%, 41%, 38%, 39%, 39%, 36%, 35%, 38%, 41%, 36%; head= 30%, 29%, 28%, 28%, 28%, 36%, 30%, 28%, 28%, 28%, 29%, 29%, 29%, 30%, 28%, 31%; interorbital width= 16%, 15%, 13%, 12%, 12%, 11%, 14%, 13%, 12%, 13%, 11%, 11%, 10%, 12%, 13%, 13%; diameter of the eye= from 6% to 8%; vertebrae= 14+18; 13+17; 13+18; 12+18, 13+18, 13+18, 13+16, 13+18, 13+18, 13+18, 12+17, 13+17, 13+18, 12+18, 13+18, 13+17.

Sexual dimorphism is shown notably in the lower contour of the body behind the anal; its is much less deep in the female; in addition, females' frontal profile (sometimes as flattened as in some Chaetodon) is so variable that they might be taken for several different species. The classic Cynolebias sexual dimorphism (dorsal and anal rays; predorsal and preanal lengths; etc.) is very strong, but difficult to place in evidence given the great variability and the similarity of color patterns. C. vandenbergi is also characterised by the presence in the male of an exceptional number of ctenoid spines (almost on each scale in some specimens) on the flanks, the preopercle, and the tail. Finally, there are 17-22 neuromasts at the bottom of each of the sensory canals of the forehead, and the lateral line extends at least 6 scales on to the caudal peduncle.


Annual, with incubation in dry peat for around 3 months, but at the end of 8 months' incubation many eggs have not begun to develop; many of the young are belly sliders. C. vandenbergi is peaceful and rather easily maintained for the genus. The parents dive into the peat to deposit their eggs. They are prolific but the eggs are sensitive to Oodinium. Newly hatched juveniles consume Artemia nauplii. The sex ratio is unequal, with females predominant. The biotope and aquarists' experience with the fish will be reported in Fromm (in prep.) and in Hoetmer and Van den Berg (in prep.).


The species is known from 16 collecting sites (see fig. 1) in the high Chaco, in the vicinity of Filadelfia in northwestern Paraguay. The limits of its distribution are unknown.


C. vandenbergi belongs to a group of Cynolebias species with medium to large size; with deep and rhomboidal form; who do not prey on congeners; unpaired fins without long filaments, and rounded in addition; and with a southern distribution; viz., adloffi, bellottii, carvalhoi( ?), cinereus, melanoorus, vandenbergi, and viarius.


This species is dedicated to Leen Van den Berg and his son Arjen, of Maarn, the Netherlands, its codiscoverors with the Fromms.

Important note: the study and diagnosis of this species turned out to be formidably complex. Even after many tests, the possibility that it actually comprises two different species can not be entirely ruled out : extreme variability in the same sex in morphology, number of rays, presence or absence of particular neuromasts or of ctenoid spines; variability of certain osteological characters; reversal of characteristic features of male and female coloration, confirmed by aquarists; and selective courtship behavior that is difficult to understand. The conservative approach has prevailed here because of the impossibility of finding distinctive, stable, and objective criteria and because of the remarkable stability of the D/A displacement, of scale counts in the longitudinal series, and of numbers of vertebrae.

Cynolebias monstrosus, new species (fig. 4).

Holotype. MNHN 1994-1110, male, 105.5 mm SL amd 128.9 mm TL Paraguay, Boqueron department, near La Serena (Station LV 94-27). 21.94 S; 56.97 W. Leen Van den Berg, 15 March 1994, coll. and Jan Willem Hoetmer, dep.

Paratype. MNHN 1994-1111, female, with the same data as the holotype.

Paratypes. ANSP 169974, 1 pair, of which the male will be transferred to MNHNP (number on demand), from a pool by the road from Filadelfia to Fortin Toledo, 32.3 km south of the Ruta TransChaco (Station DF 92-110); ANSP 169973, 1 pair (Station DF 92-107) and ANSP 169975, 2 males ( ?) (Station DF 92-107B), of which the largest has been transferred to MNHN, No 1993-3619; Dan Fromm, October 1992, coll. and dep. ZMA 121281, 3 individuals (Station LV 94-33); ZMA 121284, 4 males (Station LV 94-33); ZMA 121285, 1 pair (Station LV 94-28); NMW-92899, 1 individual (Station LV 94-23). Leen Van den Berg, 1994 coll. and Jan Willem Hoetmer dep.


Of very great size, probably, with C. porosus, the largest of the genus; similar to C. elongatus and C. prognathus, but easily distinguished by the color pattern, composed of 13 to 14 prominent bars on the flanks and by morphomeristic data (notably, the much higher number of scales in the longitudinal series, the strong reduction in the depth of the body behind the anal, with a form generally elongate, aproximately from 28-30% to 14-18% in SL); additionally, C. monstrosus has approximately 104 neuromasts (a previously unheard-of number) on the forehead in the canals characteristic of Cynolebias, as well as 6 neuromasts near the postorbital rim; the eye is relatively very small and not prominent, so much that the greatest width of the head is 30-40% greater than the interorbital distance.

Life colors

The male and female differ little, the female having paler coloration : both have the characteristic black bar across the eye, but at an angle of around 120 degrees, in contrast to the majority of Cynolebias, in which the angle is from 160-180 degrees, as well as 15 vertical to slightly oblique (/) dark grey bars on a lighter base, more intense in the male and varying with the fish's mood; the male displays weak coloration in the vertical fins : red in the dorsal, with grey blotches, and blue-green in the anal, also a black edging while the tail is uniformly dark grey. The female's color is generally less intense and all fins are transparent.

Colors in alcohol

Both sexes, with a very intense black vertical bar below and above the eye, making an angle, preceded and followed by a light area, then a grey zone, on the preopercle; the flanks display the narrow dark grey vertical bars of the live animal, but with more contrast, and between them six wider light bars; the area near the base of the anal is whitish, increasingly darker towards the distal edge of the fin, with a black border in the male; in the rear center part of the male's dorsal fin there are 6-10 intense small flames.

Size, proportions, and formulas

Males around 150 mm TL, females a little less, in aquarium specimens of the 'giant' population; but this is a maximum, for the other populations collected remained relatively smaller.

Morphological and meristic data of the 8 first types mentioned (holotype first and in bold face, then alternatively female and male, the last individual being another male) are, after radiophotographic confirmation : D= 18, 16, 16, 17, 17, 16, 17, 17; A= 23, 22, 23, 22, 21, 21, 21, 22; D/A= +6, +7, +8, +7, +6, +7, +7, +8; LL= 66+9, 68+3, 77, 63, 64, 65, 74, 67; TRAV.= 21, 23, 26, 20, 20, 20, 22, 24; L.S. (in mm)= 105.5, 86.0, 76.9, 73.8, 65.1, 54.1, 65.2, 68.8; L.T. (in % of SL)= 122%, 122%, 127%, 118%, 122%, 124%, 123%, 117%; P.D.= 68%, 70%, 70%, 68%, 70%, 68%, 70%, 70%; P.A.= 60%, 60%, 58%, 57%, 57%, 60%, 56%, 57%; P.V.= 54%, 53%, 50%, 49%, 49%, 51%, 50%, 50%; depth at the anal= 27%, 28%, 33%, 28%, 28%, 27%, 31%, 27%; head= 37%, 40%, 37%, 36%, 38%, 38%, 38%, 38%; interorbital width= 17%, 14%, 15%, 15%, 14%, 13%, 16%, 14%; diameter the eye= 4%, 5%, 4%, 5%, 4%, 4%, 4%, 5%; snout= 11%, 11%, 8%, 8%, 9%, 9%, 9%, 10%; vertebrae= 15+22; 14+19; 12+21; 13+21; 13+21; 13+21; 12+21; 13+22.

For comparison, in the single type of elongatus (which we have examined and for which Dr. B. Herzig has kindly sent a radiophotograph), counts are : D= 19; A= 23; D/A= +3; LL= 48; L.T.= 122%; P.D.= 68%; P.A.= 67%; P.V.= 59% : depth at the anal= 30%; vertebrae= 14+21.

The general form is massive, notably the head, which is very long and wider than the rest of the body, making one think immediately of a predator; the teeth in the outer row are numerous, unicuspid, and strongly recurved towards the inside. Sexual dimorphism is weak (morphology) to nonexistent (number of rays in and insertion of the vertical fins), as in Cynopoecilus and al., but contrary to the other Cynolebias.


Annual, with incubation period in dry peat on the order of 3 months; it is rather difficult to maintain, for the genus, because of its aggressive behavior and ultrarapid growth : keeping a pair in the same aquarium for more than two hours is risky, and even the females are agressive among themselves; paradoxically, a lone specimen can be maintained for months in a 1 liter aquarium; the adults consume earthworms up to 10 cm long, also other fishes and their own siblings; breeders dive into the peat to spawn; the first results of captive breeding were deceptive : none of 120 juveniles obtained and rescued from cannibalism was female; aquarists' experiences with the fish will be reported in Hoetmer and Van den Berg (in prep.) along with its biotope.


The species is known from seven collecting sites in the high Chaco, in the vicinity of Filadelfia, in northwestern Paraguay; the limits of its distribution are unknown. The type locality of C. elongatus is " La Plata, " (by assumption, near the town, 25.88S, 58.91W), around 1500 km from the monstrosus sites; its other known collecting sites are all near Buenos Aires. The type locality of prognathus is " Las Maravillas " in southeastern Uruguay (33.65S, 53.67W in Huber, 1994), roughly 1300 km from the monstrosus sites.


C. monstrosus belongs to a group of very large species of Cynolebias having a cylindrical body and a massive appearance; with more than 45 scales in the longitudinal series; agressive; eating large prey including their smaller congeners such as C. chacoensis and C. bitteri; having unpaired fins without long filaments; without gonopodium; and having a rather southern distribution. Viz., C. elongatus, C. monstrosus, and C. prognathus. C. porosus, type species of the genus Cynolebias Steindachner 1978, and other forms described by Costa from Brazil (albipunctatus, griseus, leptocephalus and perforatus) could easily be included in the group, for they share certain of the traits listed above (with, always, a somewhat lower LL), as well as, to a lesser degree, cherodophilus, schreitmuelleri and wolterstorffi. This group could make up the typical subgenus Cynolebias s.s., containing several superspecies.


From the latin monstrum, referring to the species' shape and behavior; common name given by Dan Fromm " pike-like monster. "

History : the species was discovered 10 October, 1992 (ANSP 160073); however, Dan Fromm reports that specimens collected previously are cataloged in MHNHP.


Cynolebias ("Simpsonichthys") chacoensis Amato, 1986 (figs 5 & 6)

Material. ANSP 170272 and 170273, respectively 1 male and 2 females and 1 pair, collected at km 565 of the Ruta TransChaco, approximately 59 km SE of the type locale (Stations DF 93-21 and 93-25). Dan and Pat Fromm, dep. 7 and 9 June 1993. ZMA 121273 and 121287, 8 and 3 individuals respectively (Station LV 94-36);

MNHN 1994-1109, 2 pairs (Station LV 94-27). Leen Van den Berg 1994, coll. and Jan Willem Hoetmer dep. NRM 20232 and UFRJ 3030, respectively 1 male and 3 individuals (Station LV 94-36). Leen Van den Berg 1994, coll. and J. Huber dep.


Of rather small size; with acuminate fins bearing filaments in the dominant male, as in many small brazilian Cynolebias; with with dress similar to that of C. nigripinnis of Uruguay and Argentina, composed of sky blue dots on the flanks and fins, on a dark grey to black ground color; the number of dots varies, two distinct populations, separated by less than 100 km having been collected, one heavily spotted (a hundred or so, cf. fig. 5), the other with many fewer spots (around thirty, cf. fig. 6); as for the females, intrapopulation variation is greater than interpopulation. After preservation, the male is very dark, and all the fin rays turn black.

Size, proportions, and formulas

Males around 45 mm TL, females a little less, after rearing in the aquarium.

Morphological and meristic data of six specimens examined, 3 males and then 3 females, are, after radiophotographic confirmation : D= 20, 24, 24, 17, 17, 19; A= 25, 27, 27, 21, 21, 23; D/A= +6, +5, +5, +6, +4, +5; LL= 28, 27, 26, 29, 27, 26; TRAV.= 13, 12, 11, 14, 12, 12; CIR= 14, 13, 14, 13, 13, 14; L.S. (in mm)= 25.5, 28.4, 23.2, 27.8, 27.9, 29.0; L.T. (in % of SL)= 125%, 136%, 135%, 123%, 125%, 126%; P.D.= 50%, 49%, 53%, 60%, 57%, 57%; P.A.= 50%, 48%, 47%, 60%, 53%, 54%; P.V.= 47%, 45%, 41%, 47%, 46%, 46%; depth at the anal= 30%, 33%, 33%, 33%, 32%, 32%; head= 28%, 30%, 28%, 30%, 32%, 29%; interorbital width= 9% to 13%; diameter of the eye= 8% to 9%; vertebrae= 13+14; 13+15; 11+14; 14+14, 12+14, 12+15.

In comparison, measurements published by Amato for the types are : D= 23 (males); 17-20 (females); A= 26 (males); 22-24 (females); D/A= +3 (drawing of a male) to -3 (drawing, probably in accurate, of a female); LL= 30 (males); 26-29 (females).

Considerable sexual dimorphism, as in all of the Cynolebias in this group. 24 round frontal neuromasts, not shaped like half of a coffee bean as is usual; apparently no neuromasts around the eye and in the preopercular canal; males' ventrals reach the second anal ray while the longer pectorals reach the 68.0pt; mso-text-raise:6.0pt">th or 7th.


Annual, incubation in dry peat lasting around 4 months; peaceful (the males' filaments are not damaged) but fragile and rather less easily maintained than the norm; divers; several pairs can be kept together; very prolific, but many eggs fail to begin development and the majority of the young are belly-sliders; aquarists' experiences and its biotope will be described in Fromm (in prep.) and in Hoetmer and Van den Berg (in prep.).


Described from a pool at km 624 from Asuncion on the road from Mariscal Estigarribia to Lagerenza (20.98S, 61.32W). It is reported here from five sites in the high Chaco in the vicinity of Mariscal Estigarribia, in northwestern Paraguay. The limits of its distribution are unknown, the most distant points at which it has been collected being around 100 km apart.


Oddly, and in contrast to the other new paraguayan Cynolebias, C. chacoensis is closely related not to other southern species, but rather, like C. bitteri, to species living in the brasilian plateau. All are characterized by acuminate vertical fins in the male; filamentous extensions of the unpaired fins not limited to the terminal rays in the dominant male; small to medium size; rather deeper in the fore part of the body; meristics by high and similar numbers of dorsal and anal rays (most often 20-24) and low dorsal-anal displacement. Thus defined, this group composed of several superspecies contains : boitonei, chacoensis, flammeus, flavicaudatus, fulminantis, hellneri, heloplites, izeksohni, magnificus, notatus, santanae and zonatus.

The taxon Simpsonichthys Carvalho 1959, described as a monotypic genus for the species boitonei because of its lack of ventrals, will serve as a name for this subgeneric group and that is what we propose here (see also below for other distinctive characters). However, this first subdivision of the genus Cynolebias as formerly understood, must be seen as a preliminary attempt, while awaiting a major publication from Costa (pers. comm.). Simpsonichthys, as defined here, may be the object of a new subdivision, of the type that has been proposed (by ourselves, among others) for the african genera Aphyosemion, Epiplatys, and Nothobranchius, within whom a subgenus corresponds to a superspecies or a homogenous group of allopatric superspecies; this is the reason why we placed the taxon Simpsonichthys in quotation marks in the title : in that event, C. chacoensis would receive, with others, a different subgeneric name, to be assigned, for it is quite different from C. boitonei, the type species of Simpsonichthys (cf. fig. 11).

Cynolebias (" Plesiolebias ") bitteri (Costa, 1990) (fig. 7).

Material. MNHN 1994-1112, 1 male and 2 females (Station LV 94-34). Leen Van den Berg, 16 March 1994, coll. and J. Huber dep. ANSP 170422 and 170423, respectively 23 individuals, in one lot and 1 pair in another, collected at km 565 of the Ruta TransChaco (Stations DF 93-21 and 93-25). Dan and Pat Fromm, dep., 7 and 9 June 1993. Of the lot of 23, 1 male and 3 females have been transferred to MNHN, No 1993-3617. Dan Fromm reports in addition (comm. pers.) that six individuals from DF 92-122 are in ANSP, as lot 173087. ZMA 121275, 4 individuals (Station LV 94-36); ZMA 121286, 1 female (Station LV 94-39); MNHN 1994-1106, 3 individuals (Station LV 94-38). Leen Van den Berg, 1994 coll. and Jan Willem Hoetmer dep. UFRJ 3031, 5 individuals (Station LV 94-36). Leen Van den Berg, 1994 coll. and J. Huber dep.


C. bitteri is characterized by a small size (less than 50 mm TL), by slight sexual dimorphism, even if visually the females appear more elongate, and, in the male and in the other Plesiolebias, a unique color pattern came up of irregular claret to chestnut oblique bands (/), Prussian blue coloration in the vertical fins and in the ventrals, also extended; both sexes have in addition a black bar across the eye and a small black blotch immediately to the rear of the opercle.

Proposed new type locality

As was mentioned in the introduction, Costa (1990a) described the species without a type locality. Taking account of the importance of this bit of information for Cyprinodonts, where cryptic species, separated only by details of coloration, are legion, we propose to establish an originating locality for the species, especially since all of the males collected in its region display a similar color pattern, comparable to that described and figured by Costa. It is locality LV 94-34 which has been chosen. But it was Dan Fromm who rediscovered it at locality DF 122, near Teniente Ochoa, 13 October 1992, in the company of C. vandenbergi and T. aplocheiloides. In all, eight collecting sites are reported here, all located in the vicinity of Mariscal Estigarribia. The limits of its distribution are unknown.

Size, proportions, and formulas

Males around 50 mm TL, females a little less, after rearing in the aquarium.

Morphological and meristic data for six specimens examined, 3 males (the first from locality LV 94-34), then 3 females are, after radiophotographic confirmation : D= 12, 12, 10, 10, 12, 9; A= 18, 20, 18, 17, 18, 18; D/A= +8, +8, +7, +8, +7, +8; LL= 24, 24, 23, 25, 24, 26; TRAV.= 11, 10, 11, 9, 10, 10; CIR= 15, 14, 14, 13, 13, 15; L.S. (in mm)= 37.6, 27.6, 21.5, 24.3, 25.1, 27.5; L.T. (in % of L.S.)= 127%, 125%, 127%, 127%, 124%, 130%; P.D.= 69%, 72%, 68%, 72%, 70%, 72%; P.A.= 61%, 61%, 60%, 64%, 59%, 65%; P.V.= 51%, 48%, 47%, 49%, 50%, 50%; depth at the anal= 31%, 31%, 29%, 30%, 28%, 30%; head= 30%, 32%, 33%, 33%, 30%, 33%; interorbital width= 14%, 15%, 11%, 14%, 12%, 14%; diameter of the eye= 9%, 8%, 8%, 9%, 8%, 8%; vertebrae= 11+14; 11+14; 11+14; 12+14, 11+13, 12+14; in three other specimens : 11+14; 11+15; 12+14.

Sexual dimorphism exists, but is much less marked than in the deep-bodied Cynolebias. One notes several series of conical teeth, one in three of the outer row being larger; the male has frontal scalation of type E.


Annual, with incubation in peat lasting around 2 months; it is peaceful (almost fearful) but fragile and easily maintained for the genus; spawning behavior would be unusual, shared by the other Plesiolebias ; the male approaches the female in a series of complex movements, he does not position himself above her as normal in the genus, but at the time of egg deposition takes up, with the female, an oblique position with respect to the substrate; many of the eggs fail to develop and disappear; newly hatched juveniles can consume newly hatched Artemia, or, better, Paramecia; growth is relatively slow, compared to that of other sympatric Cyprinodonts; sexual maturity occurs at five months. Aquarists' experience will be described in Fromm (in prep.) and Hoetmer and Van den Berg (in prep.), as will the biotope.


Costa has published twice on the species: first in 1990 for the description in Plesiolebias because it shares 3 characters with the other species of that genus: breeding behavior (parents do not dive into the substratum), oblique bands on sides, and reduced length of pectorals; second in 1991, to distinguish it from the other Plesiolebias in an unstable position (" incertae sedis " species) because it does not share the following 4 synapomorphies: a rectangular basihyal, a reduced number of vertebrae (less or equal to 25), a second and third enlarged epibranchial, an horizontal process of the quadratum, enlarged posteriorly, and the larger size of the female. After the study of some specimens, we cannot confirm the criterion of the number of vertebrae and, owing to the high infraspecific variability we feel necessary that the osteological diagnoses are founded on an important number of specimens. The species is, from its external morphological characters taken together, unquestionably very near to the small species of Cynolebias gathered here under the subgenus name Simpsonichthys, even if the sexual dimorphism does not translate into the measured proportions and even less in the meristical data (the female " looks " more elongate than the male; all vertical fins of male are acuminate, even with filaments; its pectorals are longer, reaching the fifth of the ventrals length; its ventrals are longer too, reaching the sixth or the seventh ray of the anal fin); however it may also be linked to the subgenus Leptolebias of Cynopoecilus and to Campellolebias owing to its breeding behavior, by the reticulated pattern on opercle in both sexes and by maybe the length of the pectorals relatively smaller (and the value of the index, see further).

Paradoxically, Costa (1991) is inclined to bring it in fine nearer to the genera allied to Rivulus, which for us illustrates well the difficulty of the systematics of these fishes and their heterogeneity at the genus level as we have shown before (1992). Consequently and due to the greater difference between the typical subgenus of Cynolebias and Sympsonichthys, we propose to downgrade Plesiolebias at the subgeneric level (see addendum).


Preliminary discussion of the systematics of Cynolebias and allied genera

Since our short review of the genus Cynolebias (1981), Costa has considerably improved our knowledge of it : systematic fieldwork in the interior of Brazil, still under way; first use of osteology; comparative systematics.

In Killi-Data (1994), our general report on the Cyprinodonts, we counted 82 taxa described in the genus and its allies, of which we considered 62 valid. Of the 41 valid species in the genus Cynolebias, 23 have been described since 1981.

While adding the three species described here, it seemed useful to sketch a division of the genus into homogenous groups; even though we did not generate all of meristic data used and because of frequent sexual dimorphism they have been restricted to males, we wanted to test the multivariate analysis we used for the genus Rivulus (Huber, 1992 : 73), especially taking advantage again of an index, calculated as Index = (Dorsal rays + Anal rays + Dorsal-Anal displacement) * Scales in the longitudinal series (I = D + A + D/A) * LL), which discriminates well.

Table 2, in which the species are ranked in decreasing order of the index, makes a succession of homogenous groups clearly visible. They will be given generic or subgeneric rank after further fieldwork by Costa.

  cm Dm Am D/Am LLm Dm - Am Index
Cynolebias (Cyn.?) cheradophilus 7.5 20 21 5 85 -1 3910
Cynolebias (Cyn.) monstrosus 15.0 17.0 22.0 7.0 69.6 -5 3202
Cynolebias (Cyn.) prognathus 12.0 17 24 5 62 -7 2852
Cynolebias (Cyn.) elongatus 14.0 19 24 3 47 -5 2162
Cynolebias (Cyn.?) wolterstorffi 7.0 20 25 6 41 -5 2091
Cynolebias (Cyn.) porosus 15.0 18 20 7 40 -2 1800
Cynolebias ("Cyn.bel") vandenbergi 9.0 24.8 29.0 4.0 30.8 -4 1783
Cynolebias (Cyn.) perforatus 12.0 17 20 8 39 -3 1755
Cynolebias ("Cyn.bel") nonoiuliensis 10.0 20 24 5 35 -4 1715
Cynolebias ("Cyn.bel") cinereus 6.0 22 24 7 32 -2 1696
Cynolebias ("Cyn.bel") bellottii 7.0 22 28 8 29 -6 1682
Cynolebias (Cyn.) leptocephalus 8.0 18 21 4 38 -3 1634
Cynolebias (Cyn.?) schreitmuelleri 5.0 18 23 5 35 -5 1610
Cynolebias (Cyn.) albipunctatus 12.0 17 19 5 39 -2 1599
Cynolebias ("Cyn.bel") melanoorus 6.0 25 25 5 29 0 1595
Cynolebias ("Cyn.bel") viarius 6.0 20 23 5 32 -3 1536
Cynolebias ("Cyn.bel") adloffi 6.0 22 26 3 29 -4 1479
Cynolebias (Cyn.) griseus 8.0 22 22 1 31 0 1395
Cynolebias ("Simpsonichthys") chacoensis 5.0 20 24 4 28 -4 1344
Cynolebias ("Simpsonichthys") flavicaudatus 6.0 23 23 -2 29 0 1276
Cynolebias (Simpsonichthys) heloplites 5.0 23 24 -3 29 -1 1276
Cynolebias ("Cyn.whi") myersi 4.5 19 23 5 27 -4 1269
Cynolebias ("Cyn.whi") whitei 6.0 15 21 7 29 -6 1247
Cynolebias ("Simpsonichthys") magnificus 4.0 23 21 2 27 2 1242
Cynolebias ("Cyn.nig") nigripinnis 7.0 24 23 -3 28 1 1232
Cynolebias ("Cyn.whi") bokermanni 6.5 16 22 6 28 -6 1232
Cynolebias ("Simpsonichthys") hellneri 6.0 21 22 4 26 -1 1222
Cynolebias ("Cyn.nig") patriciae 4.0 22.8 24.5 2.3 24.5 -2 1217
Cynolebias ("Cyn.nig") luteoflammulatus 4.5 23 20 -4 31 3 1209
Cynolebias ("Cyn.nig") costai 4.0 21 24 3 25 -3 1200
Cynolebias ("Simpsonichthys") fulminantis 5.0 21 21 2 27 0 1188
Cynolebias ("Cyn.nig") affinis 5.0 22 22 -2 28 0 1176
Cynolebias ("Cyn.whi") izecksohni 5.0 16 22 4 28 -6 1176
Cynolebias ("Simpsonichthys") flammeus 4.0 21 22 2 26 -1 1170
Cynolebias ("Simpsonichthys") notatus 3.5 23 20 2 26 3 1170
Cynolebias (Simpsonichthys) santanae 3.0 19 19 3 28 0 1148
Cynolebias ("Cyn.nig") cyaneus 5.0 22 22 -3 28 0 1148
Cynolebias ("Cyn.nig") gymnoventris 5.0 23 21 -3 28 2 1148
Cynolebias ("Cyn.whi") constanciae 5.0 14 21 6 27 -7 1107
Cynolebias ("Cyn.nig") alexandri 5.0 22 22 -2 26 0 1092
Cynolebias (Simpsonichthys) zonatus 4.5 17 19 4 26 -2 1040
Cynolebias (Simpsonichthys) boitonei 5.5 22 18 3 24 4 1032
Cynopoecilus (Cynop.) melanotaenia 4.0 16 19 0 29 -3 1015
Cynopoecilus (Leptolebias) nanus 3.0 12 18 6 27 -6 972
Cynopoecilus (Leptolebias) aureoguttatus 4.0 13 17 3 29 -4 957
Cynopoecilus (Leptolebias) fractifasciatus 4.0 14 18 6 24 -4 912
Cynopoecilus (Leptolebias) opalescens 4.0 13 18 4 26 -5 910
Cynopoecilus (Leptolebias) citrinipinnis 4.0 12 17 5 26 -5 884
Cynopoecilus (Leptolebias) leitaoi 3.0 13 16 6 25 -3 875
Cynopoecilus (Leptolebias) minimus 4.0 13 18 4 25 -5 875
Cynopoecilus (Leptolebias) marmoratus 3.0 13 16 2 28 -3 868
Cynopoecilus (Leptolebias) splendens 3.0 13 18 5 24 -5 864
Campellolebias chrysolineatus 4.0 17 18 -2 26 -1 858
Terranatos dolichopterus** 4.0 14 16 -3 26 -2 702
Cynolebias (Plesiolebias) bitteri 4.0 11 17 7 24 -6 840
Campellolebias dorsimaculatus 4.0 15 17 -1 27 -2 837
Cynolebias (Plesiolebias) damascenoi 2.5 10 14 6 27 -4 810
Cynolebias ("Cyn.lac") lacortei 5.0 11 15 5 25 -4 775
Cynolebias (Plesiolebias) aruana 3.0 9 16 7 24 -7 768
Cynopoecilus (Leptolebias) cruzi 4.0 12 15 5 24 -3 768
Campellolebias brucei 4.5 14 16 -1 26 -2 754
Cynolebias (Plesiolebias) glaucopterus 3.0 9 16 6 24 -7 744
Cynolebias (Plesiolebias) lacerdai 2.0 11 15 4 23 -4 690
Cynolebias (Plesiolebias) xavantei 3.0 12 16 2 23 -4 690


note: * approximate averages, based on very limited material ** erratum corrigendum


We will not create new taxa here, but this approach allows some homogenization of the relative levels; reuse of the name Simpsonichthys, which had been regarded as a synonym; reassessment of the status of Plesiolebias, proposed here as a subgenus, in consideration of additional distinguishing characters within Cynolebias.

We thus propose below a reassignment of species to homogenous entities on the basis of a limited number of criteria.

Ten groups are temporarily created on the basis of males' : maximum length in cm; form (cylindrical, deep, massive, average); presence or absence of a strong reduction in the body's depth at the anal; sexual dimorphism or dichromatism; the index; large or small difference in the numbers of dorsal and anal rays; number of scales in the longitudinal series (" LL "); reproductive behavior; and geographic distribution. Dorsal-anal displacement (D/A), which is important for diagnosing species, does not seem to be important in defining these groups (perhaps superspecies ?), contrary to what we found for non-annual Rivulins. Also see Table 2 for meristic data.

1. Cynolebias : general shape deeper; temporary melanic pattern vertical.

1.1 Cynolebias s.s. Very large size; cylindrical form; a marked decrease in the depth of the body at the anal; very weak sexual dimorphism and dichromatism; the highest index (3910 - 1395, several superspecies); dorsal with 17-20 rays, more in the anal; all fins rounded; no gonopodium; head large and broad with relatively small eye; very aggressive, preying on small sympatric congeners; reproduce by diving into the substrate (" divers "); very broad distribution, from the extreme south to the Sertao of Brazil.

1.2 " Cyn. bel. " Large size (6 - 10 cm); body compressed and very deep; major reduction of depth at the anal, but high number of circumpeducular scales; marked sexual dimorphism but less marked dichromatism; a rather high index (1783 - 1479); round dorsal and anal; their bases long but unequal, the anal longer; high LL; no gonopodium; medium eye, often larger than the snout; divers; southern distribution, to the limits of the interior plateau of Brazil.

1.3 " Cyn. nig. " Small; body compressed; significant decrease in depth at the anal, but few circumpeduncular scales; very marked sexual dimorphism and dichromatism; average index (1232 - 1092); rounded dorsal and anal; their bases long and equal; average LL; no gonopodium; medium eye, equal to the snout; divers; southern distribution to the limits of the interior plateau of Brazil.

1.4 " Cyn.whi. " Medium to large size; cylindrical, compressed towards the rear; marked dimorphism and dichromatism; average index (1269 - 1107); acuminate dorsal and anal; much longer-based anal; average LL; no gonopodium; medium eye, equal to snout; divers; coastal distribution, in Brazil.

1.5 Simpsonichthys. Small to medium size; compressed; progressive dimunition of depth rearwards from the ventrals; very strong dimorphism and dichromatism; average index (1344 - 1032); acuminate dorsal and anal; long bases, and nearly equal, sometimes with a longer dorsal; average LL; no gonopodium; relatively large eye, equal to the snout; divers; widely distributed in the interior plateau of Brazil and adjacent areas.

Note (cf. supra) : this subgenus is composed of several superspecies that are often sympatric : species in which certain characters deviate from Simpsonichthys s.s. are in quotation marks in Table 2.

1.6 Plesiolebias. Small; compressed and rhomboidal; slight decrease in depth rearwards from the ventrals; weak dimorphism and dichromatism; low index (840 - 690); acuminate dorsal and anal; short-based, anal much longer than dorsal; low LL (23 - 24); no gonopodium; relatively large eye, equal to snout; spawn on the substrate's surface; distribution limited to Mato Grosso and adjacent areas.

2. Terranatos and " Cyn.lac. ": Genus or subgenus of Cynolebias. Two small relict ( ?) species. Cylindrical, weakly compressed towards the rear; slight dimorphism and dichromatism; low index (858-778); dorsal, anal, and tail acuminate and having filaments; anal and dorsal bases short and equal; average LL; eye relatively large, equal to snout; restricted and relict distribution, the monotypic genus Terranatos in Venezuela and C. lacortei in the Araguaia drainage of Brazil; external similarity of these species could reflect phylogeny, in which case similar forms may exist in the region between them, or chance.

3. Cynopoecilus and allied forms : generally less deep-bodied, horizontal melanic temporary pattern

3.1 Cynopoecilus s.s. (monotypic subgenus). Small; cylindrical, compressed towards the rear; slight decrease in depth towards the rear; weak sexual dimorphism and dichromatism; low index (1015); dorsal and anal acuminate and superposed; anal longer-based than dorsal; tail oval or lanceolate; average LL; vestigial gonopodium (first rays of the anal joined); relatively large eye, pointed snout; spawn above the substrate; coastal distribution, southern Brazil and Uruguay.

3.2 Leptolebias (subgenus of Cynopoecilus). Small; cylindrical, compressed towards the rear; very slight decrease in depth towards the rear; slight dimorphism and dichromatism; low index (972 - 864); dorsal and anal acuminate and opposed; anal longer-based than dorsal; tail often lanceolate or oval; low LL; no gonopodium; medium eye; spawn above the substrate; distributed coastally in Brazil.

3.3 Campellolebias. Small, and the species very similar; cylindrical, compressed towards the rear; slight decrease in depth towards the rear; marked dimorphism and dichromatism; low index (858 - 754); dorsal and anal acuminate and opposed; anal longer-based than dorsal; tail often lanceolate or oval; low LL; functional gonopodium; medium eye; reproduces above the substrate; relict coastal distribution in southern Brazil.

Each group is thus separated from the others by at least one key criterion, excluding reproductive behavior and distribution. The groups' positions and their relative levels must, however, be refined by study of their osteology using representative series, taking account of the great intraspecific variability. Cynolebias s.s. appears to be some distance from all of the others. Plesiolebias has some characters in common with Simpsonichthys, but also with " Cyn. whi. " and Leptolebias. " Cyn. nig. " could be viewed as intermediate between " Cyn. bel. " and Simpsonichthys.

We hope that this preliminary contribution which proposes for the first time a complete reclassification will be improved upon.

Study of annual Rivulins collected in the genera Trigonectes, Pterolebias, and Neofundulus, allied to Rivulus

Trigonectes aplocheiloides, new species (fig. 8)

Holotype. MNHN 1994-1104, male, 75.9 mm SL and 93.1 mm TL.

Paraguay, Boqueron department, 74 km from Mariscal Estigarribia in the direction of Americo Picco, (Station LV 94-35). 21.30 S; 60.51 W. Leen Van den Berg, 16 March 1994, coll. and Jan Willem Hoetmer, dep.; maintained in aquarium for 4 months.

Paratype. MNHN 1994-1105, female, 69.8 mm SL and 83.6 mm TL, with the same data as the holotype.

Paratypes. ANSP 169976, 3 individuals, the largest probably a female, respectively 69.1, 34.6, and 25.9 mm SL, Paraguay, KM 464.1 on the Ruta Transchaco (Station DF 92-103); ANSP 169977, 1 individual (Station DF 92-109); ANSP 169980, 1 juvenile (Station DF 92-122), Dan Fromm, 9 to 13 October 1992, coll. and dep. ANSP 170416, 2 individuals (Station DF 93-21); ANSP 170420, 1 individual (Station DF 93-25). Dan and Pat Fromm, 7 June 1993, coll. and dep.


Of great size relative to the average of the genus, distinguished from all of the other Trigonectes by the color of the flanks (yellow-green spots, not red-brown), by the morphology which makes it appear like, to the point of being mistaken for, a fish of the Cyprinodont genus Aplocheilus from the indo-malaysian subcontinent (frontal profile greatly flattened, fusiform body, dorsal fin set far back, with, additionally, a generally ochre coloration)

Life colors

The male and female differ little, the female having paler coloration, as in Rivulus : both have two grey-black bars from top to bottom of the eye; a yellow band with orange speckles near the base of the anal; and ( ?) an oblong bright yellow blotch on the forehead; additionally, in the male the distal part of the anal and the lower part of the caudal are bright orange. The flanks of both sexes are covered by 8-10 longitudinal series of bright yellow to green spots on an ochre to rose base, somewhat like Rivulus bahianus; a shining yellow preopercular blotch is likewise very distinct; the male's other fins are orange ventrals, the dorsal with chestnut reticulations and a vestigial basal band as in the anal, and finally the tail streaked with brown; the female's fins have similar but paler coloration; take note of an elegant little touch, that the ventrals are edged in white.

Color in alcohol (after 12 hours fixation)

Males, with unspotted flanks, dorsal and anal orange at the base, additionally with dark spots near the base and on all of the dorsal; the lower abdomen is orange; a gray vertical zone appears clearly on the tail to the rear of the peduncle; the female is similar, except for the flanks, which are spotted and the tail, dorsal, and anal, which are completely yellow; in both sexes the lower lip is dark, as is the preopercular region.

Size, proportions, and formulas

Males around 100 mm TL, females a little less, after rearing in the aquarium. Morphologic and meristic data of the 7 types mentioned (holotype, male, first and in bold face, then 6 probably females) are, after radiophotographic confirmation : D= 13, 14, 12, 12, 12, 13, 13; A= 17, 17, 16, 16, 17, 17, 16; D/A= +7, +6, +6, +7, +8, +7, +7; LL= 36+4, 37, 35, 33, 34, 35, 37; TRAV.= 11, 11, 9, 10, 10, 11, 11; L.S. (in mm)= 75.9, 69.8, 69.1, 34.6, 25.9, 28.4, 36.6; L.T. (in % of L.S.)= 123%, 120%, 124%, 126%, 127%, 125%, 125%; P.D.= 73%, 72%, 74%, 73%, 72%, 74%, 73%; P.A.= 64%, 67%, 67%, 64%, 62%, 66%, 66%; P.V.= 50%, 53%, 54%, 52%, 50%, 54%, 53%; depth of the anal= 23%, 20%, 20%, 20%, 19%, 21%, 20%; head= 28%, 29%, 27%, 32%, 32%, 31%, 30%; interorbital width= 14%, 15%, 13%, 13%, 12%, 11%, 12%; diameter of the eye= 6%, 7%, 7%, 7%, 8%, 8%, 6%; vertebrae= 15+18; 16+18; 15+17; 15+18, 16+18, 16+17, 15+18.

The pectorals are long for a Trigonectes : 21% of SL in the male and 18% in the female; the ventrals are long, but much less than in the other members of the genus : in males they reach only to the second or third anal ray.

There are around 22 circumpeduncular scales and 24-30 predorsal scales. There is no outstanding sexual dimorphism : ventrals a little longer in males, but vertical fins not pointed in either sex (respectively, very long and filamentous in T. balzanii).


The species is annual, with a dry period on the order of 6 months or more; it is difficult to maintain for the genus : only 10 progeny have been obtained so far, 1 female and 9 males; the parents dive into the peat to deposit their eggs; no intra- or interspecific aggressiveness has been reported; aquarists' experience will be described in Hoetmer and Van den Berg (in prep.), along with the biotope.


The species is known from five collecting sites in the high Chaco, in the vicinity of Filadelfia, in northwestern Paraguay; the limits of its distribution are unknown. T. balzanii, a species common to Brazil and Paraguay, is known to the northeast and to the south in the drainage of the Rio Paraguay. We doubt that the two species are sympatric.


Although is it clearly distinguished from the other members of the genus, T. aplocheiloides belongs in Trigonectes s.s. The genus is very close to Rivulus and a more extensive study could even merge them if new characters are not used in the analysis. In fact, the criteria commonly believed to separate the two genera (filamentous ventrals, annual development, reproductive behavior) are no longer supportable because of the discovery of intermediate Rivulus species and because of the new diagnosis of Rivulus (Huber, 1992).

Costa (1990b), with the description of two new brazilian Trigonectes species, tried to redefine the genus on the basis of osteological characters, but his data set was unfortunately too limited.

Etymology: similar to Aplocheilus, a Cyprinodont genus of the old world.

Trigonectes balzanii (Perugia, 1891) (fig. 9).

Materiel ZMA 121271, 15 individuals (Station LV 94-20); ZMA 121280, 1 individual (Station LV 94-39); MNHN 1994-1103, 1 pair (Station LV 94-20). Leen Van den Berg 1994 coll. and Jan Willem Hoetmer, dep. ANSP 173086 and UFRJ 3032, respectively 6 and 4 individuals (Station LV 94-20). Leen Van den Berg, 1994 coll. and J. Huber dep.


Of medium to large size, smaller but more elongate than T. aplocheiloides, with frontal profile less flat and the male's fins much longer; little sexual dimorphism; dichromatism is stronger than in the new species, but the female's colors are very subdued, as in Rivulus; the male's color pattern corresponds well to Costa's (1990a) figure and description; on a base of shining yellow green at the front, tending towards blue at the rear, are 8 discontinuous lines of reddish brown dots of which only half continue behind the dorsal's origin, the other half fusing into thicker, irregular, prominent lines; all of the fins, except the colorless pectorals, are densely spotted with dark brown on a yellow base; the lower part of the tail and anal is vivid red (a typical trait, that seems to be shared by all known species in the genus); a black border adorns the unpaired fins, in contrast to the thread-like ventrals, where it is white.

Size, proportions, and formulas

Males around 75mm TL, females a little less, after rearing in the aquarium.

Morphological and meristic data of two individuals from station LV 94-20 (male, then female) are, after radiophotographic confirmation : D= 11, 11; A= 15, 15; D/A= +9, +8; LL= 33, 32; TRAV.= 10, 10; CIR= 20, 22; L.S. (in mm)= 53.9, 51.7; L.T. (in % of L.S.)= 131%, 125%; P.D.= 76%, 78%; P.A.= 70%, 73%; P.V.= 53%, 56%; depth at the anal= 23%, 21%; head= 28%, 29%; interorbital width= 13%, 13%; diameter of the eye= 7%, 7%; vertebrae= 15+16; 15+15.

Sexual dimorphism is marked : ventrals and vertical fins long and sometimes filamentous, but evidently much less than in Cynolebias.


Annual, duration of incubation in dry peat on the order of 4 months; easily maintained for the genus, and can be recommended to killiphiles who have not worked with annuals; breeders dive into the peat to deposit their eggs; no inter- or intraspecific aggressiveness has been reported; T. balzanii is very prolific; newly hatched fry can immediately take Artemia nauplii; aquarists' experience with the fish and its biotope will be reported in Hoetmer and Van den Berg (in prep.).

Pterolebias sp. aff. longipinnis Garman, 1895.


ZMA 121274, 2 individuals, collected 10 km W of Mariscal Estigarribia, on the Ruta TransChaco (Station LV 94-37). Leen Van den Berg, 1994 coll and Jan Willem Hoetmer dep. ANSP 170427, 4 subadults or juveniles mixed with some subadult Rivulus, collected 8 km from the Puente Remanso on the road to Clorinda, across the Rio Paraguay from Asuncion (Station DF 93-29). Dan and Pat Fromm, Walter Gomez, J. Barnett, Edgar Ramirez and Julio Casiles, 13 Juin 1993 coll. and D. Fromm dep.


Very large; cylindrical form comparable to Rivulus; dorsal set far back, its insertion far behind the anal's (D/A > +10); spade-shaped tail, with the outer rays threadlike; pectorals are short and ventrals long, in males reaching the 5th or 6 8.0pt;mso-text-raise:6.0pt">thfont-family: Arial"> ray of the anal; the male's color pattern is made of bluish white chevrons (>>>) on the flanks and especially a unique post-opercular mark which evokes a butterfly (a preordained name, if the fish had to be proclaimed new), made up of two oblong orange to vermilion patches, connected to each other, by another one, small, black; the preopercular region is silvery, like the unpaired fins, of which the dorsal and anal in addition bear two series of oval dots alternately golden and chestnut.

Identification and distribution

The designation P. sp. aff. longipinnis is conservative and temporary; its closeness with P. longipinnis and not P. luelingi is a consequence of Thomerson's (1984) having synomized these two species. Having seen the types of neither, we find it impossible to discuss this proposition in light of the new collections from Paraguay; let us recall that the first step in resolving this question will be to obtain and study living topotypes of P. longipinnis, unknown in life since its description in 1895; P. sp. aff. longipinnis' distribution is unknown; as of now it is the only member of the genus known from Paraguay; unconfirmed information suggests that populations of similar fishes might occur in other countries of the Rio Paraguay drainage.

Size, proportions, and formulas

Males around 100mm TL, females a little less, after rearing in the aquarium.

Morphological and meristic data of 2 individuals from station DF 93-29 (2 males) are, after radiophotographic confirmation : D= 9, 9; A= 19, 18; D/A= 12, 10; LL= 30, 29; pDOR= 23, 24; TRAV.= 9, 9; CIR= 15, 16; L.S. (in mm)= 33.4, 27.4; L.T. (in % de SL)= 149%, 144%; P.D.= 75%, 82%; P.A.= 60%, 65%; P.V.= 44%, 49%; depth at the anal= 22%, 22%; head= 29%, 27%; interorbital width= 11%, 12%; diameter of the eye= 8%, 8%; vertebrae= 16+14; 16+15.

Frontal scalation is type E. Strong sexual dimorphism : ventrals and vertical fins long and sometime with filaments, but rather less than in Cynolebias.


Annual, duration of incubation in dry peat around 3 months; easily maintained for the genus; breeders dive into the peat to lay their eggs; weak inter- and intraspecific aggressiveness.

Neofundulus ornatipinnis Myers, 1935 (fig. 10).


ANSP 169979, 1 female (Station DF 92-114); ANSP 169981, 1 male, Walter Gomez, coll. and Dan Fromm, dep., 1992 (also taken at the same site by Dan and Pat Fromm in 1993). ANSP 170415, 11 individuals, probably 2 males and 9 females (Station DF 93-22);

ANSP 170417, 13 individuals of which 4 have been transferred to MNHN, No 1993-3616 (Station DF 93-24); ANSP 170418, 1 male (Station DF 93-12); ANSP 170419, 1 female (Station DF 93-11);

ANSP 170421, 7 individuals, probably 3 males and 4 females (Station DF 93-19). Dan and Pat Fromm, 5 - 8 June 1993 coll. and dep. ZMA 121283, 4 individuals (Station LV 94-25); ZMA 121288, 7 individuals (Station LV 94-28); MNHN 1994-1113, 3 individuals (Station LV 94-24). Leen Van den Berg, 1994 coll. and Jan Willem Hoetmer dep. UFRJ 3033, 1 male (Station LV 94-35). Leen Van den Berg coll. and J.Huber dep. Aberrant population : MNHN 1994-1108, 5 individuals, 1 male and ( ?) 4 females (Station LV 94-32). Leen Van den Berg, 15 March 1994 coll. and Jan Willem Hoetmer dep.


Large and rather massive in appearance, with a cylindrical body, very similar to Rivulus; much higher LL than in other members of the genus; dorsal-anal displacement slight (+ 2 to +4); both of these fins inserted rather to the rear, and with equal bases; the eye and snout are small; patterns of frontal scalation and neuromasts identical to those of Rivulus (type D or E); in all these aspects the resemblance is so striking (e.g., to R. caudomarginatus) that only more thorough osteological comparisons will be able to determine the eventual level of differentiation.

Life colors

Males are particularly handsome during courtship displays; the underside and ventrals are bright orange, the flanks are traversed by 8 longitudinal series of red dots on a blue green base; the dorsal has black and yellow reticulations; the anal has a pale yellow sub-basal band, contrasting with an intense black ground coloration; the tail also, but there the yellow band is interrupted to form independent crescent-shaped blotches; the eye is orange; the opercle and pectorals are peppered with grey; as for the female, she displays a modest dress of subdued colors : the fins' ground color is clear and only the anal's yellow sub-basal band adds a touch of color; a more or less large greyish black blotch, higher than wide, appears behind the opercle in both sexes, more or less strongly according to mood. Populations from near Asuncion and from the high Chaco differ little in color pattern, setting aside some details which we consider minor (but which Dan Fromm, who has collected both populations, thinks quite important; for him the shape of the male's tail is again distinct); on the other hand, the aberrant form's coloration diverges more : the tail's crescent band is continuous, dark yellow, and located nearer the edge, the anal is all yellow, except for a dark band at mid-depth; the flanks are duller, with some chestnut spots on a yellow ground. It is not certain, though, that these differences would persist in larger series.

Morphological and meristic data of 8 individuals (1 from the low Chaco near the Rio Paraguay; then data for three " normal " individuals from the high Chaco, in italics; and finally for four individuals of the aberrant form) are, after radiophotographic confirmation : D= 15, 16, 14, 16, 15, 14, 15, 15; A= 15, 17, 16, 16, 18, 17, 17, 17; D/A= +4, +4, +2, +2, -2, 0, -1, -2; LL= 36+6, 37+8, 38+5, 36, 35, 37+5, 34, 35; TRAV.= 12, 14, 13, 13, 13, 13, 14, 12; CIR= 23, 18, 19, 20, 18, 19, 18, 19; L.S. (in mm)= 46.9, 60.9, 51.1, 41.4, 69.9, 56.2, 51.4, 46.6; L.T. (in % of L.S.)= 120%, 123%, 120%, 119%, 123%, 122%, 126%, 124%; P.D.= 70%, 70%, 67%, 68%, 67%, 69%, 72%, 66%; P.A.= 68%, 68%, 67%, 66%, 67%, 68%, 72%, 67%; P.V.= 57%, 57%, 53%, 54%, 59%, 57%, 58%, 57%; depth at the anal= 23%, 24%, 21%, 21%, 24%, 19%, 20%, 20%; head= 29%, 28%, 29%, 30%, 30%, 27%, 32%, 32%; interorbital width= 17%, 16%, 15%, 16%, 14%, 13%, 13%, 13%; diameter of the eye= 6% … 7%; vertebrae= 15+17; 16+17; 16+17; 16+16, 15+19, 16+18, 17+17, 17+18. 23-27 predorsal scales. Frontal scalation variable, clearly identifiable in only two specimens, 1 type D and the other type E. Sexual dimorphism weak; the male's ventrals a little longer, but vertical fins rounded in both sexes.


Annual (but seems to live longer in the aquarium : one pair was still alive 8 months after collection as subadults). Incubation on dry peat lasts around 6 months; Souza Santos (1979) studied reproductive behavior and incubation in a Brasilian population now identified as N. parvipinnis. N. ornatipinnis is easily kept, but in spite of that has not yet reproduced in captivity. Breeders dive deep into the peat to spawn, but no eggs have been recovered or hatched after incubation. Hoetmer and Van den Berg (in prep.) will describe the biotope and their experiences with the fish.


Type localities of the two Neofundulus species described from Paraguay are not far apart, one being an east bank tributary of the Rio Paraguay (paraguayensis), the other (ornatipinnis) on the west bank. In his revision of the genus Costa (1988) regarded the two species as valid. He reported that each was based on a single type specimen, respectively a female and a male. He separated them on the basis of the number of scales in the transverse series (9 and 10-11, respectively), the number of circumpeduncular scales (16, 18-19), presence/absence of a black postopercular spot, the form of the tail (oval/lanceolate or truncate), and the length of the pectorals (reaching the fourth or second ray of the anal). In addition, he separated his two new species from Brazil from them by the relative position of dorsal and anal fins (D/A = +1 or +2 in the Paraguayan forms, +5 or +6 in the Brazilian ones); these pertinent observations are based on only a few specimens and our measurements of specimens from the Chaco are intermediate, with D/A = +3 to +4.

As the color patterns Costa reported are very much like those of our specimens, there is a strong suspicion that the Paraguayan material represents only a single polymorphic species. Not having examined the types, and because of the aberrant population discussed below, we will not take that step, and will identify our specimens as N. ornatipinnis, unfortunately the more recent name, because of their geographic origin (west of the Rio Paraguay); rather deep shape; the rounded shape of the tail, higher than long; the higher number of dorsal and anal rays; and the number of scales (TRAV = 12-14).

Remark on the aberrant population

A population with very aberrant behavior and somewhat less aberrant in some morphometric characters (especially D/A = 0 to - 2) and color pattern was collected at site LV 94-32. In the wild and in the aquarium, all of the fishes observed have behaved differently from standard Neofundulus (Jan Willem Hoetmer, pers. comm.); they leap vertically as much as a meter, as do Rivulus (Huber, 1992) and do not bury their eggs deeply in the substrate, but place them on supports in the upper levels of the aquarium.

Jan Willem Hoetmer intends to test whether the aberrant behavior and differences in coloration are stable in the second captive generation, and anticipates crossing it with the standard form.


N. ornatipinnis is very close to the other species in the genus (guaporensis, paraguayensis, parvipinnis, and acutirostratus), whose diagnoses remain to be restated taking the Paraguayan material into account.


Thanks to teams of enthusiastic amateurs, the first significant approach to Paraguayan Cyprinodonts has been proposed for the annual forms.

Much fieldwork remains to be done; in fact, collections have been made in only 10% of the country, life colors from the type localities of taxa as important as Rivulus punctatus, Neofundulus paraguayensis, and N. ornatipinnis are not yet known, and additional extremely limited, therefore not discussed here, collections allow us to expect the discovery of interesting forms.

The bases of the enormous morphological (including the sensory organs) meristic, and behavioral variability established above, and not only in Cynolebias vandenbergi, as well as habitat partitioning in the wild also remain to be understood.

This augurs well for the future and will provide the stimulus necessary for new expeditions by killie fanciers.


We are especially grateful to Prof. J. Daget (MNHN), Dr. M. L. Bauchot (MNHN), R. H. Wildekamp (Gemert), Dr. E. Maury and J. Braga (MACN, Buenos Aires), and to an anonymous reviewer for having reviewed the manuscript. Dr. W. J. E. M. Costa (UFRJ, Rio de Janeiro) also reviewed it, but his notes and new publications reached us only after it had been finalized. We thank as well Mme. de Soutter (MNHN) for having checked scale counts for the types of C. monstrosus.

Bibliography :

Amato, L.H. 1986. Seis Especies nuevas del Genero Cynolebias Stdr, 1876, de Uruguay y Paraguay (Cyprinodontiformes, Rivulidae). Communicaciones Zoologicas del Museo de Historia Natural de Montevideo, 11 (162) : 4-7, fig. 3-6.

Carvalho, A.L. de. 1959. Novo Genero e novo Especie de Peixe anual de Brasilia, com uma Nota sobre os Peixes anuais da Baixada Fluminense, Brasil. Bol. Mus. Nac. (N.S.) Rio de Janeiro, 201 : 1-10.

Costa, W.J.E.M. 1988. Sistematica e Distribuiçao do genero Neofundulus (Cyprinodontiformes, Rivulidae). Rev. Brasil Biol., 48 (2) : 110, fig.

· . 1989. Redescriçao do genero Cynolebias (Cyprinodontiformes, Rivulidae), com a descricao de uma nova especie da bacia do Rio Tocantins. Commun. Mus. Cien. PCURS, Sér. zool. Porto Allegre, 2 (9) : 181-190, tab.

· . 1990a. Descriçao de um genero e duas especies novas de peixes anuais do centro da America do Sul. Communicaciones de Museu de Ciencias, Pontifica Univ. Catolica do Rio Grande do Sul, 2 (1989) (10) : 195-198, fig.

· . 1990b. Systematics & Distribution of the Neotropical annual Fish genus Trigonectes (Cyprinodontiformes, Rivulidae), with description of two new species. Ichthyol. Explor. Freshwaters, 1 (2) : 141-144, fig.

· . 1991. Systematics & Distribution of the Neotropical annual Fish genus Plesiolebias, with Description of a new species. Ichthyol. Explor. Freshwaters, 1 (4) : 375, fig.

Huber, J.H. 1981. Cynolebias heloplites n. sp. Supp. Killi Revue (Killi Club de France), 5 (Octobre) : 15 pp., 2 photos, figs., tab.

· . 1992. Review of Rivulus. Ecobiogeography - Relationships.

Cybium Suppl., Société Française d'Ichtyologie Publ. : 586 pp., 40 pls., 85 figs, 8 tabs, 13 maps.

· . 1994. Killi-Data 1994. Updated checklist of taxonomic names, collecting localities & bibliographic references of oviparous Cyprinodont fishes (Cyprinodontoidei); in french, english, & german. Cybium, Soc. fr. Ichtyologie, Ed., Paris : 1-366.

Parenti, L.R. 1981. A phylogenetic & biogeographic Analysis of Cyprinodontiformes Fishes (Teleostei, Atherinomorpha). Bull. Amer. Mus. Nat., 168 (4) : 335-557, 99 figs.

Souza Santos P.F., de. 1979. The Southamerican annual Fish Neofundulus paraguayensis (Eigenmann & Kennedy, 1903). J. Amer. Killi. Ass., 12 (2) : 33-40, 15 figs.

Abbreviations of institutions' names : ANSP : Academy of Natural Sciences of Philadelphia (U.S.A.); MNHN : Museum national d'Histoire naturelle de Paris (France); ZMA : Zoölogisch Museum Amsterdam (The Netherlands); MNHNP : Museo National de Historia Natural del Paraguay (Asuncion); NMW : Naturhistorisches Museum Wien (Austria); NRM : Naturhistorika Rijks Museum, Stockholm (Sweden); UFRJ : Universidad Federal do Rio de Janeiro (Brazil); MACN : Museo Argentino de Ciencias Naturales (Buenos Aires); MHNG : Musée d'Histoire Naturelle de Genève (Switzerland).

ADDENDUM (May 1995)

After the present work had been completed, Costa described (Rev. fr. Aquariol. 21 :April, 1995) two new genera and shared with us his suggestions on our tentative grouping of the species of Cynolebias and its allies, in the light of a revision that he is preparing.

* damascenoi, which we had not been able to examine due to lack of material, is separated from the genus Plesiolebias, together with a new cryptic species, bellus, to be placed in the new genus Stenolebias.

* lacortei is separated from Cynolebias, together with a new cryptic species, formosa, to be placed in the new genus Maratecoara, which displays affinities with the monotypic genus Terranatos : Costa thus joins our analysis in isolating lacortei and relating it to Terranatos, but he neither indicates in what respects the two taxa/genera are separable nor what justifies making a distinction at the generic level. Other material belonging to this species flock, probably phylogenetic, will doubtless soon be collected, since a population of T. dolichopterus has been collected on a river island in Venezuelan Amazonia (R. Brousseau, pers. comm.), located 470 km south of the type locality and around 2500 km northwest of that of lacortei.

* bitteri will be removed from the genus Plesiolebias and the group of genera allied to Cynolebias to be placed in the group of genera allied to Rivulus, in a separate entity (to be named ?); moreover, Costa indicates to us that he " sees no problem in keeping it provisionally in Cynolebias ".

Thus, Costa's concept of the group Cynolebias and its allies leads to considering eight distinct genera valid, at the extreme opposite of Parenti's (1981), equally cladist, which recognizes only one of them. Plesiolebias sensu restricto would contain only three species (xavantei, glaucopterus, and lacerdai), Stenolebias would regroup two (damascenoi and bellus), like Maratecoara ( lacortei and formosa). These differences in appraisal are not at all a problem, genera and subgenera concepts not benefiting of reckoned building criteria: they only reflect personal views; this is not major compared to the objective of a constant improvement of knowledge.



Cynolebias patriciae, new species (fig 2, male; 3 female; 4, juvenile).

Cynolebias vandenbergi, new species (fig. 5, male; fig. 6, female and fig. 7, aberrant phenotype; fig. 28, drawing of a radiophotograph of a male ANSP 169800).

Cynolebias monstrosus, new species (fig. 8, male; fig. 9, female; fig. 10, male from the giant population; and fig. 11, male's head).

Cynolebias ("Simpsonichthys") chacoensis Amato, 1986 (figs 12, 13, males, and fig. 14 female)

Cynolebias ('Plesiolebias') bitteri (Costa, 1990) (fig. 14, male and 15, female).

Trigonectes aplocheiloides, new species (fig. 16, male, and fig. 17, male and female)

Trigonectes balzanii (Perugia, 1891) (fig. 18 and 20, male, and 19, female).

Pterolebias sp. aff. longipinnis Garman, 1895 (fig. 21, male).

Neofundulus ornatipinnis Myers, 1935 (fig. 22 and 24, males; 23, female of the normal form; 25, male, 26 and 27 females of the aberrant form "leaper").

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