A Record of the Black-headed Sea Snake, Hydrophis melanocephalus (Reptilia: Elapidae), from Wakayama Prefecture, Japan

Abstract

A large gravid female of Hydrophis melanocephalus was captured in early December 2004 from offshore of Wakayama Prefecture, west-central Honshu, Japan. This is the first confirmed record of this species from waters adjacent to Honshu. The female gave birth to three juveniles (one born alive, and the other two stillborn) within three days of capture. Autopsy of the female after her death in one month later yielded another developing embryo and four undeveloped eggs in oviducts. This suggests that her actual litter size was four and potential litter size was eight.