Towards a reevaluation of the species diversity of the large cyprinids from the Epulu River in the D.R. Congo
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The Epulu River, one of the right bank affluent of the Ituri (headwater of the Aruwimi), is separated from the latter by the Ngoy waterfalls (±15m high). Due to its isolation, it houses an impoverished but interesting fish fauna, which is mainly composed of cyprinids. For this study, 16 meristics and 30 morphometrics have been studied on 200 Epulu River specimens (182 Labeobarbus and 18 Varicorhinus). Currently three species of Labeobarbus have been identified: L. macroceps which seems endemic to the Epulu and L. caudovittatus and L. mawambiensis, which both appear to be more widespread in the Congo basin. In addition, we found one Varicorhinus species, representing the first record for this genus in this part of the Congo basin. As the specimens could not be attributed to any of the currently known species they are here referred to as V. sp. Epulu . In addition to these well identifiable species, the Epulu sample also contains 21 specimens which appear to be morphologically intermediate between L. mawambiensis - characterized by a narrow mouth with fleshy lips and an apparent mental lobe on the lower jaw, two pairs of long barbels and the last unbranched dorsal fin ray rigid - and Varicorhinus sp. Epulu - characterized by a rectangular mouth with a horny cover and a horny comb on the anterior edge of the lower jaw, one pair of short posterior barbels and the last unbranched dorsal fin ray flexible. The presence of these intermediate morphotypes is reminiscent of the scenario inferred for the Inkisi River (Lower Congo, RDC) where it has been shown that these intermediate morphotypes represent interspecific hybrids. It is therefore hypothesized that hybridization, although apparently less intense, is also ongoing in the Epulu River. Analogously to the Inkisi River case, parental species and intermediate morphotypes could not by distinguished by mtDNA (COI) analyses.
CitationWalanga, A.; Decru, E.; Snoeks, J.; Vreven, E. (2013). Towards a reevaluation of the species diversity of the large cyprinids from the Epulu River in the D.R. Congo. , Fifth International Conference of the Pan African Fish and Fisheries Association (PAFFA5),