Cytogenetical studies on fishes. II. Karyotypes of four carangid fishes.

All four carangid fish species (Trachurus japonicus, Caranx equula, C. sexfasciatus, and Alectis cilialis) studied here showed a diploid chromosome number of 48. The karyotype comprises all acrocentric pairs (nos. 1 to 24) in Alectis cilialis, but the largest chromosome pair (no. 1) changed into subtelocentrics in Caranx equula and C. sexfasciatus. In Trachurus japonicus the karyotype was different from the above three species by consisting of 15 biarmed chromosome pairs (nos. 1 to 15) and 9 acrocentric pairs (nos. 16 to 24). The sex chromosomes can not be identified in these 4 species. Based on these findings relation between the karyotype differentiation and species diversity of carangid fishes was discussed.