By Popoola Michael Olaoluwa and Adeniran Isaac Idowu
Garra trewavasae Monod 1950 is a Cyprinid fish known only from the Jos Plateau, Nigeria. However, there are controversies over its taxonomic placement. Unfortunately, there is no information about its karyotype which is an important data useful to assess its taxonomic status. In this study we provide for the first time the karyotype of G. trewavasae using the conventional Giemsa staining technique. The diploid number (2n) was represented by 50 chromosomes and this corresponds to the diploid number reported for all other African Garra species. The number of chromosome arms (NF) was 85 and it falls within the range reported for African Garra species. The karyotypic formula was 1M + 9m + 3sm + 2st + 35t. However, unlike other African Garra species, a big unpaired metacentric chromosome which corresponds to the X chromosome according to earlier studies on African Garra species was detected. The sex of the species studied is therefore a male.