GENUS AMBLYELEOTRIS (GOBIIDAE) OF JAPAN AND GEOGRAPHICAL VARIATIONS OF A. JAPONICA TAKAGI

Abstract

1. New species Amblyeleotris maculata was described on the three specimens collected at the shallow water of Sesoko Island, Okinawa Island, and A. jasciata (Herre) which is recorded for the first time from Japanese water was re-described on the specimens from Nansei Islands and Ogasawara Islands. 2. Amblyeleotris japonica Takagi has the remarkable variations among three populations of Nansei Islands, Shirahama and Ogasawara Islands. These geographical variations were analysed chiefly based on the number of fin rays and scales, the proportional characters, the form of pelvic fins and presence or absence of the scales of the median part of nape and those of pectoral base. 3. The developmental changes of pelvic fins is remarkable in A. japonica collected at Shirahama. The uniting membrane of juveniles about 10 mm in standard length is fully developing and the form of pelvic fins is disk-like, but that of specimens growing up more than 12 mm reduces suddenly and pelvic fins become separated. 4. The morphoiogical characters of A. maculata, A. fasciata and three geographical types of A. japonica were compared and the key to these species and types were established.