Raorchestes annandalii (Boulenger, 1906)

Deuti, Kaushik, Ray, Sukumar, Bag, Probhat & Dey, Swapan Kumar, 2017, Amphibians of the Duars area of Northern West Bengal, Records of the Zoological Survey of India 117 (3), pp. 221-241 : 236-237

21. Raorchestes annandalii (Boulenger, 1906)

1906. Ixalus annandalii Boulenger, J. Asiat. Soc. Bengal., Ser. 2, 2: 385.

Common Name: Darjeeling Bush Frog (English). Size: Snout-vent length 20-24 mm (males) and 27-30 mm (females).

Distinguishing features: Head is broader than long and the snout-length is almost equal to the diameter of the Specimens examined: 4 ex: A 11931-A 11934 from Buxa Fort , Buxa Tiger Reserve , Alipurduar district , West Bengal (26°45’323”N, 89°34’868”E) collected on 29-30.v.2014. The measurements of the frogs collected are given below in millimeters :

Size: 16-23 mm (snout-vent length).

Diagnostic features: This is the smallest frog in the hills of the duars area of northern West Bengal. It is arboreal with digital pads on both fingers and toes and a slender body. Snout is pointed and distinctly projecting over the lower jaw. Eyes are large but the inter-orbital space is slightly broader than the upper eyelid. Ear-drum is very small but distinct. Males have a large, thin-walled sub-gular vocal sac which is equal to the body size when fully inflated. Fingers free of web. The tips of the fingers have truncated small pads. Toes have small truncated adhesive pads with a small amount of webbing. Skin on the upper and lower sides of the body is smooth but the sides of the body between the fore and hind limbs as well as on the belly and under the thighs are granular. A strong glandular skin fold runs from behind the eye to the shoulder.

Colour: Dorsum is greyish-brown with a light bar between the eyes and a light broken stripe from the posterior corner of the eye to the groin. Limbs have darker stripes. Ventrum is yellowish-white with some brown speckles, dots and marblings. During the breeding season the underside of the thighs of males become intensely red.

Habitat: Bushes and shrubs growing on the hill-sides from about 500 meters to higher elevations. Rarely descends to the ground.

Remarks: Smallest but common frog found in the lower hilly areas of the duars area of northern West Bengal. Reported earlier from West Bengal ( Sarkar, Biswas and Ray, 1992).