Northernmost records of Branchiostegus okinawaensis from Amami Islands, Kagoshima Prefecture, Japan.

Abstract

Seven specimens of Branchiostegus okinawaensis (Branchiostegidae), previously known only from Okinawa Prefecture, were collected from Amami-oshima and Kikai-jima islands, Amami Islands, Kagoshima Prefecture, Japan, being the first records of B. okinawaensis from Kagoshima Prefecture and northernmost records for the species. In addition, reexamination of the species confirmed the existence of a dark mid-dorsal ridge on the dorsal surface of the head from the interorbital to the dorsal-fin origin, although some authors described the absence of such a ridge. Although B. okinawaensis has been regarded as characterized by the orbit diameter greater than the interorbital width, such was not the case in one of the Amami specimens, indicating the variable nature of the character.