Darevsky’s viper

Description

Vipera darevskii is a small venomous viper species endemic to northwestern Armenia,northeastern Turkey,and possibly also adjacent southern Georgia.No subspecies are currently recognized.In this species there is sexual dimorphism in size,color,and pattern appearance.The reported maximum total length (body + tail) for females is 42.1 cm (16.6 in).The total length of the largest male was 25.8 cm (10.2 in).The dorsal surface of V.darevskii has a light brown to grey background color,with a dark brown to black (often broken) zigzag pattern along the back,and a single row of small dark blotches on each side of the body.The belly has a pattern of numerous grey or black dots.In females the belly is greyer,while in males it is almost black with some white fragments on the edges of the ventral scales.The chin shields and labial scales are white,with few dark fang-shaped markings on the labials,which makes this species different from the related Vipera eriwanensis,which has a somewhat pink tint on the labials.In general adult males are noticeably brighter and have more color contrast compared to females.Females have a browner background color and a less pronounced brown pattern;while adult males have a relatively light background color with a yellow tint,and a dark,often black,pattern.The dorsal scales are keeled.The dorsal surface of the head anterior to the frontal (the area sometimes called the pileus) carries a complex of enlarged shields.