KARYOTYPES IN 6 SPECIES OF PUFFERFISHES GENUS TAKIFUGU (TETRAODONTIDAE, TETRAODONTIFORMES)

Chromosome studies were carried out on six species of genus Takifugu: T. niphobles, T. pardalis, T. poecilonotus, T. radiatus, T. rubripes, and T. xanthopterus, which are found commonly in coastal waters of nor thern Kyushu, Japan. Chromosome preparations were made from kidney tis sues with conventional air-dry method. Chromosome numbers were determi ned as 2n=44 and new arm numbers were determined as 46 in all the spec ies. Karyotype analyses indicated to have 4 m + 16 sm + 24 st or ac in T. niphobles, 6 m + 16 sm + 22 st or ac in T. pardalis, 12 m + 10 sm + 22 st or ac in T, poecilonotus, 8 m + 14 sm + 22 st or ac in T. radi atus and T. xanthopterus, and 10 m + 12 sm + 22 st or ac in T. rubripe s. Fundamental number (FN) of five species were determined as 66 excep t T. niphobles which had 64 in FN. Therefore, it was estimated that th e chromosome complements of these fishes were remarkably similar. So, the occurrence of the natural hybrids of this genus Takifugu might be related with similarity of their karyotypes.