Malayan pit viper

Calloselasma is a monotypic genus created for a venomous pit viper species, C. rhodostoma, which is endemic to Southeast Asia from Thailand to northern Malaysia and on the island of Java. No subspecies are currently recognized. Attains an average total length of 76 cm (30 in), with females being slightly longer than males. Occasionally, they may grow as long as 91 cm (36 in).