Divergent karyotypes of the annual killifish genus Nothobranchius (Cyprinodontiformes, Nothobranchiidae)

Abstract

Karyotypes of two species of the African annual killifish genus <i>Nothobranchius</i> Peters, 1868, <i>Nothobranchius brieni</i> Poll, 1938 and <i>Nothobranchius</i> sp. from Kasenga (D.R. Congo) are described. Both species displayed diploid chromosome number 2n = 49/50 for males and females respectively with multiple-sex chromosome system type X₁X₂Y/X₁X₁X₂X₂. The karyotypes of studied species are considerably different from those previously reported for the genus <i>Nothobranchius</i> and similar to the Actinopterygii conservative karyotype.