Abstract
The snake found on Oshima Is., Danjo Islands, has been treated as Natrix sauteri without sufficient discussion. However, this Danjo Islands snake is different from Amphiesma (formerly Natrix) sauteri in the dorsal scale rows formation, an important character in the genus, and very similar to A. vibakari in this character. Therefore, this snake is described as a new subspecies, Amphiesma vibakari danjoensis. The new subspecies is restricted to Oshima Is., Danjo Islands, Japan and characterized by lower ventral count, higher subcaudal count and higher tail ratio than in the other two subspecies of A. vibakari. Further, it shows unique features not seen in other forms of the A. vibakari group (sensu Malnate, including A. vibakari, A. sauteri and A. popei). The internasorostral contact ratio is about 0.5, far smaller than that of the others. Prefrontals have narrow contact with supraoculars. Postoculars are relatively reduced and usually three among seven supralabials enter the orbit.
