Material Examined : 3 adults and 2 juvenile.

Description & Scalation : Head triangular, distinctly broader than neck; scales on upper surface of head small, subequal, smooth. Eye with vertical pupil. Heat sensing pit between nostril and eye. Internasals larger than adjacent scales on the upper surface of head, separated by a single scale, ( internasals not separated in 2 specimens ); supraoculars narrow entire, broader than adjacent scales, 8-11 scales on a line between them; 2-3 postoculars; temporals smooth. Scales smooth, in 21 or 23 : 21 to 23 : 15 to17 rows; supralabials 9-11, first completely united with the nasal; single row of small scales between elongated subocular and supralabials; infralabials 12-14; ventrals 152-173; subcaudals 45-65, paired; tail short, prehensile, anal entire.

Description : 4 color forms seen.

1. Juvenile : Light or dark brown above, with a series of large dark brown blotches bordered with pale white on the back and similar colored stripe on each side of body. Underside pale whitish-brown. A white streak starting on the snout passing below the eye to the angle of the mouth and distinct white spots on the tips of scale row 1, starting near or back of the neck and extending on to beginning of tail. Upper lip scales blackish. Head uniform dark brown.
2. Uniform pale orangish-brown above, yellowish-cream below. Lip scales and head uniform dark orange.
3. Uniform redish-brown above, orangish-yellow below, tail underside dark orange. Upper lip scales dark redish-brown, lower lip scales orangish, head uniform blackish- brown.
4. Yellowish-brown above, with indistinct pale brown markinkgs. Underside yellowish-cream. Lip scales redish, head brown with few indistinct dark scales.

Natural History : Poorly known. Nocturnal, but also encountered during day time. Terrestrial and semi-arboreal in habits. Mostly seen around fresh-water streams, low bushes, hill slope forest floor ( on root cover ). Probably feeds on frogs, lizards and small rodents, also recorded feeding on agamid lizard. Alert and aggresive in nature, if alarmed vibrates tail rapidly and strikes with lightning speed. Not much known about its breeding biology, appears to be ovoviviparous. Grows up to 60cm.

Distribution - India : Endemic to Central Nicobar group of Islands and Car Nicobar, recorded from following Islands – Camorta, Nancowry, Katchal, Trinkat, Bompoka, Tarasa, Chowra and Car Nicobar.

External link : http://reptile-database.reptarium.cz/species?genus=Trimeresurus&species=labialis