Trimeresurus labialis

Trimeresurus labialis, commonly called Nicobar bamboo pit viper, is a venomous pit viper species endemic to the Nicobar Islands of India. No subspecies are currently recognized.

Geographic range
Found only in the Nicobar Islands of India. The type locality given is "den Nikobaren".

Description
Males may attain a total length of 42 cm (16½ in), with a tail 8 cm (3⅛ in) long; females, total length 44 cm (17¼ in), tail 7 cm (2¾ in).

Dorsally, T. labialis is brown, either light or dark, with or without darker spots or transverse bars. It may have a light streak on each side of the head, beginning at the snout, continuing under the eye, to the neck. Ventrally, it is also brown.

The dorsal scales are smooth, and are usually in 23 rows at midbody. Ventrals: 158-170 in males; 154-174 in females. Subcaudals: 60-65 in males; 46-57 in females. The subcaudals are usually double, but there may be some interspersed singles.