Calotes nigrilabris, Length of head one and half times its breadth; snout a little longer than the orbit; forehead concave; cheeks swollen in the adult male; upper head scales unequal, smooth; canthus rostralis and supraciliary edge sharp; a row of from 5 to 9 compressed spines starting from above the tympanum and extending posteriorly beyond it; diameter of tympanum about half that of the orbit; 10 to 12 upper and as many lower labials. Body compressed; dorsal scales more or less distinctly keeled, pointing backwards and downwards, except the upper two or three rows, which point strait backwards, much smaller than the ventrals, which are strongly keeled and mucronate; 42 to 50 scales round the middle of the body. Gular sac not developed, gular scales keeled, as large as the ventrals; a short oblique pit or fold in front of the shoulder covered with small granular scales. Nuchal and dorsal crests continuous, moderately developed, composed of lanceolate spines gradually diminishing in size; the longest spines on the neck do not equal the diameter of the orbit; female with a lower crest and a mere ridge posteriorly. Limbs moderate; third and fourth fingers equal; fourth toe distinctly longer than third; the hind limb reaches to the orbit or the temple. Tail long and slender; in the adult male it is markedly swollen at the base, with large, thick, keeled scales, those of the upper median row forming a slight serrated ridge (Deraniyagala, 1953; Smith, 1935 Taylor, 1953).

The body color is green with angular whitish, black-edged, transverse bars or spots. Head averaged with black; upper lips and the cheeks usually with a black streak or separated from eye by a white one or a pale bluish green stripe runs from ear to shoulder; below greenish white, some times Reddish brown vertebral band present or absent; base of the tail dark olive or brown (Deraniyagala, 1953; Smith, 1935 Taylor, 1953).

Calotes nigrilabris is recorded only from montane and sub montane forests above 1,000 m elevation, within cloud forests (Das & De Silva, 2005; Erdelen, 1984; Manamendra-Arachchi & Liyanage, 1994). Calotes nigrilabris restricted to Horton Plains, grassland around Nuwara Eliya, Hakgala and C. nigrilabris is the only species to occur also in tropical high altitude grasslands, at Horton Plains (Bahir & Surasinghe, 2005). This species is endemic to Sri Lanka. Accordingly, it might be expected to occur in the Knuckles Mountains as well as higher elevations in the central hills (Erdelen, 1984). No evidence, how ever could be obtained that this species inhabits the Knuckles, in contrast to data in Deraniyagala, 1953 (Erdelen, 1984). C. nigrilabris had density with an average of 220 individuals per hectare in Nuwara Eliya. Population sizes and percentages of males, females and juveniles were almost stable in Nuwara Eliya (Erdelen, 1988).

This is usually sub arboreal, inhabits tree trunks, hedges and shrubs, where it hunts insects, worms by day (Das & De Silva, 2005). Fernando, 1998 mentioned a short hissing of male C. nigrilabris while handling.

The female digs a nest hole in the ground and deposits 2 eggs in December. The eggs are 23 mm long by 13 wide (Deraniyagala, 1953).

Conservation status: Stable population (Manamendra-Arachchi & Liyanage, 1994), Endangered (Bahir & Surasinghe, 2005), Vulnerable (IUCN, 2007).