New insights into the relationship of the genus Episemion

The genus Episemion was described in 1987 based by five specimens found by Peter Wagner and Roland Wendel in 1986 and by Radda & Pürzl in 1987.

Thus far only one species in the Genus has been described, E. callipteron Radda & Pürzl, 1987 from a small range that covers northwestern Gabon and southeastern Equatorial Guinea. A slightly different form with an aberrant color pattern was found in Edoum in Nordgabun on the border with Gabon in south Equatorial Guinea. Radda and Pürzl wrote in their introduction that the referring this species to a specific Genus was problematic.

When comparing the dorsal and anal ray values and the position of the dorsal to the anal with all known subgenera, nothing matched.

Only a few Nothobranchius species have the similar values.

The tail fin shape is striking and only shared with Fundulosoma.

Drawing and coloring pattern correspond rather that of the genus Epiplatys

The diagnostic for deciding referral of the Genus name to either the Aplocheilinae or the Nothobranchiinae per Parenti (1981) are these criteria: 1. Rear vomer area wide at Epiplatys, very narrow in Aphyosemion 2. Epipleural ribs unharmed Epiplatys (Fig. 1 top right), feared at Aphyosemion (Fig. 1 bottom right) 3. Upper Hypuralia shared with Epiplatys, undivided at Aphyosemion 4. Absence (Epiplatys) or presence (Aphyosemion) of curved processes on the fourth epibranchialia. 5. High (Epiplatys) or low Chromosome number (Aphyosemion) 1 - 4 are only for skeletal preparations determine. Radda & Pürzl had only 5 Animals available as types should be available. That's why they could meet those criteria to not confirm. Episemion was provisional by the authors described as a subgenus of Epiplatys. In investigations of the relationship a strange representative of the Aplocheilidae (Fundulopanchax powelli), caught in the western Niger Delta the author has reviewed many features, around Aphyosemion and Fundulopanchax to be able to distinguish (Van der Zee & Wildekamp, ​​1995). In these studies are also EpiplatysArten and Episemion callipteron Service. It turned out that Epiplatys and Episemion have very little in common. These results were however in the F. powelli description not published and are therefore presented here. skeleton Rear Vomer area The vomer (a tiny bone on the Underside of the skull) is at Episemion narrow, just like Aphyosemion. Epipleural ribs furrowed


jaw

Head lower base / mandible To determine if preserved specimens belong to Epiplatys or Aphyosemion, you only need the bottom of the head to look at. Epiplatys shows a head bottom, at the transition from the gill cover to the lower jaw between eyes wide apart (Figure 4). Aphyosemion and relatives show here parallel pattern (Fig. 5).


markings
markings

Vermiform Markings

Worm like markings on the face and throat.


neuromasts
neuromasts

Head top: Frontal system The neuromasts are found on the top of the head near the mouth. Other than the E. sexfasciatus species group, all Epiplatys species have the two front neuromasts in a single dimple, (Fig. b) while all Aphyosemion, Fundulopanchax, and Nothobranchius and closely related fish have two dimples, each with single neuromast. (Fig a). Clausen noted by 1967 that the former "Roloffia" clade (Archaphyosemion, Scriptaphyosemion and Callopanchax), all have a single dimple (Clausen, 1967). Also other criteria that I examined showed that "Roloffia" and Epiplatys shared several characteristics who have not a single representative of Aplocheilidae shares with you ("synapomorphies"). The close relationship of Epiplatys and "Roloffia" was also examined by DNA proven (Murphy & al., 1999). Criteria 4 and 5 are unfortunately with Episemion not yet examined. Although Parenti's work is a milestone in the classification of the tooth carp should, should not to mention that you are inside a species group only very little material has examined. That's why the results often not very reliable when it around the lower taxonomic units is.