Hemidactylus triedrus (Daudin, 1802)

Taxon Identification

Hemidactylus triedrus (Daudin, 1802) has a large, oviform head.

Snout and Orbit Characteristics

Its snout is longer than the distance between the eye and the ear-opening, and measures 1.4 times the diameter of the orbit. The forehead is concave, and the large, suboval, oblique ear-opening is about half the diameter of the eye.

Body and Limb Size

The body and limbs are moderate in size.

Digit Structure

The digits are free, moderately dilated, with the inner digit well developed; the infra-digital lamellae are slightly oblique, with 6 or 7 lamellae under the inner digits, and 8 to 10 under the median digits.

Head Scale Granulation

The snout is covered in convex granules that may be keeled; the back of the head has minute granules mixed with roundish tubercles.

Rostral Scale Features

The rostral scale is subquadrangular, less than twice as broad as it is deep, with a median cleft along its upper edge.

Nostril Composition

The nostril is formed by the rostral scale, the first labial scale, and three or four nasal scales.

Labial Scale Count

There are 8 to 10 upper labials and 7 or 8 lower labials.

Mental Scale Features

The mental scale is large, triangular or pentagonal, and at least twice as long as the adjacent labials.

Chin-Shield Arrangement

There are four chin-shields, with the median pair the largest and in contact behind the mental scale.

Dorsal Body Scalation

The upper surface of the body is covered with small flat granular scales, and large trihedral tubercles arranged in 16 to 20 more or less irregular longitudinal series. These tubercles vary slightly in size between specimens, but the largest never exceed two fifths the diameter of the eye.

Abdominal Scale Features

Abdominal scales are large, smooth, rounded, and imbricate.

Male Preanal Pores

Males have a mesially interrupted series of preanal pores, with 6 to 8 pores on each side.

Tail Morphology

The tail is rounded, faintly depressed, and tapering. Its upper surface is covered with irregular, small, smooth imbricated scales and rings of large, pointed, keeled tubercles, while its underside has a median series of transversely dilated plates.

Dorsal Coloration

The dorsal coloration is light pinkish brown, usually with more or less defined transverse darker bands bordered by pure white tubercles that are surrounded by deep-brown rings. Juveniles have very regular dark brown bars, with four dark bars between the head and the hind limbs.

Head Color Pattern

A more or less defined dark-brown streak, edged with white along its upper margin, runs along the side of the head through the eye.

Ventral Coloration

The lower surfaces are white.

Body and Tail Length

The length from snout to vent is 3.7 inches, and the tail is 3.8 inches long.

Species Distribution

This species is distributed in Sri Lanka, Pakistan (from Karachi eastward), and India.

Subspecies Range

The race lanka is found in Sri Lanka, with its type locality recorded as Ceylon.