A karyological analysis of the artificial hybridization between Clarias gariepinus (Burchell, 1822) and Heterobranchus longifilis Valenciennes, 1840 (Pisces; Clariidae)

A karyological analysis of an artificial hybridization (reciprocal crosses) between two African clariid catfish, Clarias gariepinus (Burchell, 1822) and Heterobranchus longifilis Valenciennes, 1840, was performed. C. gariepinus has a standard karyotype of 2 n = 56, while H. longifilis has 2 n = 52. The hybrids revealed an intermediate karyotype (2 n = 54), and it appears as if they have totalized the haploid chromosome number of both parental species, excluding gynogenesis or androgenesis. The hybrid karyotype is considered as aneuploid, although the hybrids proved to be fertile. No variation was found in the hybrids karyotypes.