Dattatreya Night Frog

Nyctibatracus dattatreyaensis measures 36.2-41.0mm in males, 37.2-38.0 mm in females. This species has a highly corrugated dorsum, having three conspicuous dorsal transverse folds (plus other short, irregular corrugations), a single longitudinal dorsolateral fold on either side, and double longitudinal folds below that. The snout has a Y-shaped fold with the arms extending toward the eyes, and the lower lip has discontinuous glandular folds. Eyelids have short longitudinal folds. A distinct supratympanic fold runs from the posterior of the eye over the tympanum to the shoulder. The throat has numerous longitudinal glandular folds, although the rest of the ventral surfaces do not. Additional characters that help to distinguish this species in combination with the corrugated skin include a head broader than long, with a slightly projecting snout; discs on fingers and toes but with only those on the toes possessing circummarginal grooves; feet 3/4 webbed; males having nuptial pads and prominent femoral glands; and body coloration of reddish-brown or black to dark black or blackish-brown, with two light dorsolateral bands (yellowish in adults, white in juveniles). The snout length is greater than the eye diameter, and the canthus rostralis is rounded; nostrils are nearer to the eye than the snout tip. Eyes are large and protruding, with rhomboidal pupils. The tympanum is indistinct. Parotoid glands, cephalic ridges, and co-ossified skin are all absent. The pineal ocellus is also lacking. Vomerine teeth are present on two ridges posterior to the choanae, with each ridge having three spinose teeth. Males have paired vocal sacs, nuptial excrescences covering the entire first finger dorsally, and prominent, highly conspicuous elongate femoral glands. Fingers are long, unwebbed and unfringed, and expand somewhat into discs that lack circummarginal grooves but have dorsal longitudinal grooves. Relative finger length is III>IV>II>I. Subarticular tubercles are present, with a single tiny round tubercle on fingers I and II and two tubercles on finger III and finger IV. Indistinct palmar tubercle and prepollex. Hindlimbs are moderately long, but tibia are relatively short. The relative length of toes is IV>III>V>II>I. Toe V has a distinct dermal fringe. Subarticular tubercles are moderate, simple, and oval-shaped. A short, spade-shaped inner metatarsal tubercle and inner tarsal ridge are present, while the outer metatarsal tubercle is absent. Supernumerary and tarsal tubercles are lacking. The tarsus bears sparse, small spine-like warts.The dorsal coloration ranges from reddish-brown or reddish-black to brownish- black or dark black. The arm and the sides of the head have blackish brown mottling. The flanks are mottled yellow, with white spots on the raised fold edges. Ventral surfaces are translucent, except for the posterior part of the thighs, and the throat is translucent creamy white with glandular brown spots but without marbling. In males, each posterior thigh bears a raised, glossy, yellow femoral gland. Internal organs are visible through the pale, translucent venter. Hindlimbs are barred. A yellow dorsolateral band is present on each side. The upper iris is golden yellow. Male nuptial pads are light yellow.Juveniles, 20.0-22.0mm, also exhibit the distinct fold pattern of three more distinct transverse dorsal folds, plus a dorsolateral fold and two lateral folds on each side. This contrasts with juveniles of N. major, which show less corrugation than adults of the same species. The dorsolateral stripes are white in juvenile N. dattatreyaensis.The specific epithet refers to the type locality, Dattatreya Peeta, where a shrine to Lord Dattatreya is found.

This species is known only from the southern Western Ghats of India, in the Bhadra Wildlife Sanctuary in Chikmagalur district within Karnataka state. It occurs in montane shola forests. The type series was collected at 1515m asl, along a slow-flowing stream.

This species appears to be more nocturnal than diurnal. Specimens were found in or adjacent to a slow-flowing stream or in the stream, sheltering under small boulders in the water. The reddish-brown coloration camouflages this species well against the reddish iron-rich substrate.

The Dattatreya night frog (Nyctibatrachus dattatreyaensis) is a species of frog in the family Nyctibatrachidae first described in the Shola forests around the Dattatreya Peeta in the Chikkamagaluru district of Karnataka. It is still known only from this part of the Western Ghats, India.