Comprehensive DescriptionRead full entry
Diagnosis: Can be distinguished from all known species of Raorchestes by the following combination of characters: medium adult size (males less than 25.2 mm SVL), pointed snout, and coloration: flanks and groin deep brown with light gray spots, anterior thighs and inner tibia with light chocolate spots alternating with gray blotches, venter vermiculated gray and dark brown. It is similar to R. dubois but can be distinguished by its larger body size (average SVL in males of 24.1 mm, vs. 20.2 mm SVL in R. dubois), sharp canthus rostralis (rounded in R. dubois), and tibia longer than thigh (vs. shorter in R. dubois) (Biju and Bossuyt 2006).
Description: Adult males of this species have a snout-vent length 23.2 mm to 25.2 mm and the single female specimen has a snout-vent length of 29.3 mm. The head width is almost equal to the length and appears flat. The snout is pointed and slightly protruding, with a sharply defined canthus rostralis and an acutely concave loreal region. The interorbital area is flat and about equal in width with the upper eyelid. Nostrils are oval-shaped, located closer to the tip of the snout than to the front of the eye, and have a lateral flap of skin. The pupil is horizontally oval. The rounded, moderately distinct tympanum is 3x the eye diameter, and has a distinct supratympanic fold running from the posterior of the orbit to the shoulder. The large tongue is cordate and emarginate. Tongue lobes are obtuse with a sparse scatter of granules. The body is slender and sometimes slightly elongated. The forelimb is shorter than the hand. Relative lengths of the fingers are I < II < IV < III. Fingertips have discs with distinct circum-marginal grooves. Lateral dermal fringe is present on both edges of all fingers while webbing is absent. Subarticular tubercles are rounded and prominent except for tubercles III2 and IV2 which are weakly developed. All fingers have supernumerary tubercles. The oval prepollex is moderately distinct. The palmar tubercle is distinct, single, and oval. The hind limbs are moderately long with the tibia about 5x longer than wide and also longer than the thigh. Heels touch when limbs are adpressed. Relative toe lengths are I < II < III < V < IV. Discs with distinct circum-marginal grooves are present on the tips of the toes, and are wide compared to the widths of the toes. Webbing between the toes is reduced. Toe V has dermal fringe. Simple, rounded subarticular tubercles are prominent except for IV3 and V2 which are weakly developed. The distinct inner metatarsal tubercle is oval, and twice as long as toe I. All toes have supernumerary tubercles. Scattered tubercles are present on the snout and between the eyes, while more prominent, granular tubercles shagreen the upper eyelids. Granules are also present on the sides of the head, and a scattering of weekly developed granules are present on the dorsum. The upper areas of the thighs and the lower areas of the flanks are slightly granulated. The dorsal surface of the forelimb, thigh, tibia and tarsus have scattered tubercles. The surfaces of the throat, chest, belly and posterior surface of the thighs are all granular with some tubercles present. Males have a median subgular vocal sac, with a pair of openings at the base of the mandible (Biju and Bossuyt 2006).
The dorsum is light brown with irregular deep brown patches. A light brown strip runs between the eyes to form a triangular grey snout. The loreal and tympanic regions are light brown. A broad, dark brown upside-down "V" marks the back, running from the forelimbs to the hind limbs. Numerous, tiny brownish-black spots are present throughout the dorsum. The surface of the upper eyelids is light brown. The lateral sides of the abdomen have dark brown spots alternating with light gray patches. The flanks and groin are deep brown with light gray spots. The yellowish-red iris is encircled by a gray ring. The dorsal surfaces of the limbs are light brown with dark brown crossbands. The anterior surfaces of the thighs and the inner surface of the tibia have light chocolate brown spots alternating with grey patches. Ventral surfaces are gray with varying sizes of dark brown specks. The belly is vermiculated. Hands and feet are gray. In preservative the coloration is similar to life, only more faded (Biju and Bossuyt 2006).
This frog can undergo metachrosis, changing from a uniform light tan when freshly caught to brownish black after time in captivity (Biju and Bossuyt 2006).
The specific epithet honors Anil Zachariah for his support and assistance to S. D. Biju (Biju and Bossuyt 2006).