First karyotype description of Epiplatys spilargyreius (Duméril, 1861) with comments on chromosome evolution in the genus Epiplatys Gill, 1862 (Nothobranchiidae)

The African non-annual killifish genus <i>Epiplatys</i> Gill, 1862 (family Nothobranchiidae) comprises 36 valid species distributed in West, Central and East Africa. The available cytogenetic information for the genus indicates a wide variability in diploid chromosome number (2n) and number of chromosome arms (FN). Here, we report the karyotype of <i>Epiplatysspilargyreius</i> (Duméril, 1861), one of the two species with the lowest diploid chromosome number (2n = 34) in the genus, from the White Nile basin in Ethiopia. Male and female karyotypes contained 18 metacentric/acrocentric and 16 subtelocentric/acrocentric chromosomes. The number of chromosome arms is, respectively, FN = 52. Analysis of karyotype differentiation in the genus allowed us to suggest that the 2n reduction in <i>E.spilargyreius</i> and many other members of the genus <i>Epiplatys</i> is mainly due to Robertsonian translocations (reduction of 2n from 48 to 34 with stable NF = 48-52). We provide an up-to-date summary of cytogenetic data and a brief review of chromosome evolution in the genus.