APHYOSEMION PASSAROI

Aphyosemion passaroi, A New Species from South Eastern Gabon, with a Unique Colour Pattern, with a redescription of Aphyosemion decorsei.*

 

Jean H. Huber**

 

 

Aphyosemion passaroi, a new species from south eastern Gabon, with unique colour pattern.

 

Abstract:

The first in depth collections of Cyprinodonts in Gabon took place in 1975-1976 and resulted in the description of over 20 new taxa. Since then the country has been regularly visited by killi hobbyists, leading, from time to time, to the discovery of a new species like Aphyosemion passaroi, described here, which shows a unique colour pattern of a black margin on the caudal fin and which may be linked by morphology to the A. coeleste superspecies. The author takes also the opportunity of this short paper to redescribe A. decorsei (Pellegrin, 1904), to escape from a misunderstanding arisen in Wildekamp's latest publication (1993): the lectotype of this taxon exhibits a few red spots on sides concentrated behind opercle.

 

Introduction:

Gabon and Cameroon are the richest countries when it comes to numbers of species of the genus Aphyosemion. These countries have three factors which encourage the genus's speciation: a virtually total forest cover, a coastal plain and an inland hilly plateau, which are clearly differentiated and intense competitive pressure from the other fauna of the Sahel savannahs or the Congo basin. In Gabon 31 valid species have been counted, from nearly 150 collecting places. Even if all the marigots near passable roads have been fished, it is still possible to explore some less accessible marigots, and above all there is the hope of the possibility of prospecting the interior of the rich Massif du Chaillu, when roads have been built.

In July, 1993, Wolfgang Eberl, accompanied by Guido Passaro, went on his second expedition to Gabon. Their aim was to collect, in a systematic manner, the Cyprinodonts of the Massif du Chaillu. In a forest marigot, characteristic of the distribution area of A. aureum, they caught and brought back live specimens of a species, the study of which they entrusted to me. Two weeks later, another expedition, led by W. Grell, found the same species 1km east of Mavanga, that is 5 or 6 km further east on the same road.

 

Aphyosemion passaroi n. sp..

 

Holotype : MNHN 1993-293, male 25.9mm SL. 32.7mm TL. South eastern Gabon, 81.3km east of Moukabou in the direction of Koulamoutou (Station P.E.G. 93/11), 1.42 S. 12.03 E. W.Eberl and G. Passaro. 10.07.1993.

Paratypes : MNHN 1993-294, 1 female, 2 juveniles; ZSM (registration in progress), 1 individual, ANSP (registration in progress), 2 individuals; all collected with holotype. Types, maintained in aquarium during 5 months have been fixed in alcohol.

[addendum : topotypes, not bred in aquaria, have also been deposited in :

NRM Stockholm, Sweden,(NRM 28344); NMW Vienna, Austria,(NMW 92825); ZMB Berlin, (ZMB 32478) and FMNH Chicago (registration unknown as yet)].

 

Description :

A small species, with average morphology for the genus, but without the filamentous extensions in the fins, as is also the case with the other members of the A. coeleste superspecies. It differs clearly from the other members of the superspecies in colouration of the male - especially that of the caudal fin - and a few minor morphometric features, such as the less far back position of the dorsal fin.

 

Thus Aphyosemion passaroi differs from :

--coeleste in not having the bright yellow post-opercular area with red markings, but rather a slight pinkish contrast over the green-yellow base ; the sides are not sky blue but iridescent with yellow-green ; the marginal and sub marginal bands of the caudal fin are not yellow and red.

 

--ocellatum in not having the black post-opercular ocellus nor the plain yellow interior of the caudal; likewise, the anal is not plain yellow but heavily reticulated with red ; the black bar surrounds the entire caudal fin and is not restricted to the upper and lower edges ; the same is the case with the dorsal and anal fins with regard to the marginal band.

 

--citrinipinnis in not having the salmon coloured head, the heavy red spotting on the sides and the red band at the base of the anal fin ; moreover, the caudal is not plain lemon yellow.

 

--aureum in not having the red marginal bands and the yellow submarginal bands on the caudal fin and inverted on the dorsal and anal fins, nor the 'spade' shape of the caudal fin ; all the same, the basic colour of the flanks is quite similar, yellow-green with reflections, but A. passaroi has red spots on the sides.

 

 

Colour of Live Fish : Male : The basic colour of the flanks and the interior of the caudal and dorsal fins is rather unusual for an Aphyosemion ; it varies from front to rear according to mood and the angle of reflection, from yellow to green; in addition, the interior of the anal fin is equally rare in the genus: an intense red reticulation over a metallic green base; the interior of the caudal is slightly streaked with red over a green base, a few irregular red dots on the sides.

Female : The dichromism is very marked : the body is beige brown with grey spotting, rather concentrated towards the front ; the fins are unspotted.

 

Colour in Alcohol (A few minutes after fixing) :

Male:

Compared with that of A. ocellatum (P.E.G. 93/10, 4.3km east of Moukabou), its closest neighbour and geographical counterpart. In passaroi, all the area below the eye and the bottom of the head is orange-red; there is no ocellus; the black marginal bands surround all fins apart from the pectorals; the end of the caudal fin tends to become blurred in the course of time, to be replaced by a white bar and a fine grey submarginal edging; in the same way, a fine white edging appears on the anal, beyond the black marginal area. The interior of the caudal is finely streaked with grey along the rays and above all an intense red reticulation can be seen inside within the anal fin and at the base of the dorsal fin.

With ocellatum, on the contrary, a small area below the eye remains yellow; the ocellus is distinctly marked in black ; the marginal bands are restricted to the ends of the rays of the dorsal and anal fins ; the interior of the fins is unspotted yellow. The two species have in common the black band on the ventrals and lower lip. The females are identical, which is normal with Aphyosemion: brown beige body, unspotted; without marked spotting.

 

Size, Proportion and Formulae :

About 40mm total length for the male, a little less for the female, after being kept in aquarium conditions.

Frontal scalation of the 'G' type (Normal with Aphyosemion) ; the frontal neuromasts are open, not sunk into channels and, curiously enough, bordered with an intense black edging.

The morphological and meristic data of the types in the MNHN (holotype first and in bold type; abbreviations explained in Huber,1992) are, after radiophotographic confirmation, as follows :

D = 12, 10, 11, 11; A = 16, 16, 15, 15; D/A = +6, +7, +6, +7; LL = 31+2, 31+1, 30+1, 29+1; TRAV = 8. 8. 8. 8; CIR = 15, 15, 15, 16; SL (in mm) = 25.9, 21.9, 21.1, 19.7; TL (in % of SL) = 126%, 127%, 124%, 123%; PD = 70%, 68%, 70%, 71%; PA = 61%, 61%, 62%, 59%; PV = 49%, 51%, 52%, 50%; height at anal fin = 20%, 18%, 19%, 17%; head = 27%, 27%, 28%, 26%; inter orbital = 14%, 15%, 16%, 15%; dia of eye = 7%, 8%, 7%, 7%; vertebrae = 12+17, 13+15, 13+16, 12+16.

 

Remark :

A. ocellatum is isomorphic but differs from A. passaroi- in the only two specimens radiophographed - in a greater D/A shift (D/A> +8) and an extra vertebra - 30 instead of 28/29. This would need to be checked in more extensive series.

 

In the Aquarium :

The species is not annual, incubation in water being in the order of 3 weeks ; it is difficult to keep, as is the case with other Aphyosemion of the Massif du Chaillu, which object to rises in water temperature, which must not exceed 21oC.

 

Biotope :

A. passaroi inhabits the marigots typical for Aphyosemion in the primary forest; the description of the biotopes and collecting places will be described by Eberl.

 

 

Distribution :

The two known localities are small steams near Mavanga on the road from Mimongo to Koulamoutou ; in this part, the road runs along the River Onoy which is probably a tributary of the Offoué. Further east begins the distribution area of A. aureum which belongs to another drainage system, that of the River Lobo ; to the west, the geographical limit with A. ocellatum is unknown. The Onoy flows towards the north, so the distribution of the species may well extend in this direction.

Related Species:

A. passaroi belongs to the group of small species of the Massif du Chaillu, comprising A. coeleste, A. ocellatum and A. citrinipinnis (Huber & Radda, 1977); other studies will have to determine whether the new species should be connected with the A. wildekampi superspecies (wildekampi, punctatum and aureum). The hypothesis that wildekampi should be attached to the superspecies A. elegans (Scheel, 1990), on the basis of a similar caryotype, needs to be backed up in the field by the absence of sympatric populations.

 

Derivatio nominis : species named, at the request of W. Eberl, in honour of its co-discoverer, Guido Passaro, Ludwigsburg.

 

Additional Note (26.09.94 for the BKA publication only) :

Soon after the manuscript was submitted to the review board of Revue Française d'Aquariologie, the describer received further information from Wolfgang Eberl :

"The type locality is a small brook which crosses the road. On 10th July, 1993, at noon, it was only 40cm to 50cm wide and 20cm to 30cm deep. The water was crystal clear and hosted also Barbus sp. (the small component species in marigots throughout Gabon), shrimps and tadpoles.

The colour pattern of the male of A. passaroi is unique since it shows a full black circumpendular wide band in the caudal. Such a band is yellow to brown in the two other yet known examples in Aphyosemion : A. cinnamomeum and A. celiae from Cameroon."

It was Guido (Passaro) who discovered the very small creek and pushed Wolfgang to fish there. When both had collected 5 specimens ( a rare fish at this place) at first glance they thought them to be A. aureum. But the fin markings were completely different… ocellatum then … but the ocellus behind the opercle was missing… eine neue Art ! (A new species). After a long while, only 10 specimens were secured and brought back to Germany Fortunately a new collecting trip in February, 1994, enabled to catch large amounts of living material.

Elsewhere in discussions, Wolfgang Eberl intuitively proposed the hypothesis that both A. passaroi and A. aureum are frontier species of two conflicting groups, respectively the A. ocellatum superspecies and the A. wildekampi superspecies. Besides the fact, it was a proof that he had closely studied my previous papers. This hypothesis is worth studying in depth (caryotype, distribution). If valid, the colour convergence will then be based, not on fin patterns, but on the very special background colouration of the body sides.

 

Redescription of Aphyosemion decorsei (Pellegrin, 1904)

 

Reading the first volume of the series "A World of Killies" by Wildekamp (1993) has surprised us since the author takes an opposite position to all preceding authors (Huber & Scheel, 1981; Radda & Pürzl, 1987; Scheel, 1990) by considering A. decorsei as a strongly pigmented species that could be a junior synonym of elegans.

We have then reviewed again the 4 available syntypes (out of 5 mentioned in the description). They are in correct state of preservation, knowing their age and although several fins have been cut horizontally. Since these specimens have been fixed and preserved in alcohol, a subadult individual, maybe a male, has kept its red pigments: it is hereby designated as the lectotype (MNHN 1904-61), the 3 other specimens being assigned to paralectotype status (MNHN 1993-292).

With a powerful multiplier and a strong light source, it is easy to study the red punctuation on body: it is limited to the usual pattern on pre-opercular region (the so-called shield), rather little conspicuous in this case and to 2 rows of spots, rather regularly drawn: the first row along the lateral line, immediately after the opercle; the second row, below it, much shorter; no punctuation appears behind the sides or in the middle part. The number of spots is only 16 (11/5) on one side and 8 (5/3) on the other side; the fins, except Pectorals, are finely and weakly dotted; the Anal fin does not show any dark submarginal band; the upper and lower region of Caudal fin being cut, it is impossible to confirm or not the availability of red marginal bands, as mentioned in the original description; finally, all specimens show the gray reticulation along the border of scales, more or less conspicuously according to conditions of preservation, not to be confused with punctuation.

All these information are present in the remarkable description made by Pellegrin : only the meristic data are erroneous et present techniques allow us to correct them.

 

Morphological and meristic data of the MNHN types (lectotype, first and in bold type), after a radiophotographic confirmation :

D= 11, 10, 10, 10; A= 15, 15, 15, 14; D/A= +8, +9, +8, +8; LL= 27, 28, 28, 28; TRAV= 8, 9, 8, 8; CIR= 14, 15, 14, 15; Standard Length (in mm)= 21.2, 30.3, 28.9, 23.7; Total Length (as a % of SL)= 119%, 119%, 110%, 119% (n.s.); Predorsal Length= 70%, 73%, 73%, 71%; Preanal Length= 60%, 62%, 63%, 63%; Preventral Length= 48%, 49%, 50%, 49%; Height at Anal level= 20%, 18%, 20%, 20%; Head Length= 25%, 23%, 26%, 27%; Interorbitar= 13%, 13%, 13%, 13%; Eye Diameter= 8%, 8%, 8%, 8%; Vertebrae= 12+17; 13+15; 12+16; 13+16; the frontal scalation is of the G-type pattern and teeth are long and conical.

These data confirm that A. decorsei is a slender species, with a short Dorsal fin that is strongly pushed posteriorly, and inhabiting the Congo cuvette: therefore, it belongs to the Aphyosemion elegans superspecies, i.e. to the nominate subgenus ; male is spotted on anterior sides and does not show a marginal band on Anal fin. Wildekamp may have been misled by a not appropriate translation of the difficult French text by Pellegrin and by the study of an erroneously labelled series, not belonging to types.

A. decorsei looks very much like the fish collected South of Bangui, at the type locality of Epiplatys mesogramma Huber, 1980: with the code name KCF 5, its color photo has been published in Scheel (1990) and Radda & Pürzl (1987). This identification, though, cannot be considered as final, because the colouration of a subadult male is only available, and because the collecting localities of A. decorsei and of KCF 5 are separated by circa 200 km -geographical coordinates for decorsei: "Bessou, Oubanghi", 5.09 N and 19.54 E (1) and for KCF 5: 3.92N and 18.17E.

To definitely fix its status, it is absolutely necessary that live material be brought back from the type locality of A. decorsei: a wish we would like to promote.

 

(1) The discovery of A. decorsei is indirectly linked to Dr Decorse's dysentery, "after 8 days of misfortune to travel only 100 km" (not 100 m, as misprinted); he had to temporarily leave the mission led by Auguste Chevalier at Fall 1902, "to be cured at Bessou (on the Oubanghi river) and collect the faunistic components of Oubanghi". However, this locality is not mentioned either on modern maps or on the Gazetteer: owing to the insight and experience of Mrs Bauchot and Dessoutter (MNHN), the account of the expedition, often heroic, together with a map, have been found in a publication by Chevalier (1904) : on the map, Bessou is situated 25 km East of Fort Possel (today, Possel, at mouth of Tomi river with Oubangui river).

 

Translated (description of A. passaroi) for a B.K.A. publication in Killi News by Peter Watkins from the original French Publication.

* Subsequent translation of redescription of Aphyosemion decorsei by the author.

 

**Laboratoire d'Ichtyologie générale, Muséum national d'Histoire naturelle, 43, rue Cuvier, 75231 Paris cedex 05, France.

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