Ahaetulla anomala

The variable colored vine snake (Ahaetulla anomala) is a species of snake in the family Colubridae. It is the first reported sexually dichromatic snake from the Indian Subcontinent, and until 2017 was formerly regarded as a subspecies of the green vine snake, Ahaetulla nasuta.[1]

Ahaetulla anomala
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Colubridae
Genus:	Ahaetulla
Species:	A. anomala
Binomial name
Ahaetulla anomala (Annandale, 1906)

Description

This species is sexually dichromatic. Males are green and resemble the long-nosed whip snake (Ahaetulla nasuta), while females are brown in color and physically resemble the brown-speckled whipsnake (Ahaetulla pulverulenta).

Distribution

It is limited to India (Odisha, West Bengal, Jharkhand, Bihar) and Bangladesh.

Characteristics

Ahaetulla anomala shows color polymorphism and has a gradient of green and brown colour. Sexual dichromatism is rare among snakes and is mostly only documented in some groups such as vipers (Bothrops), Comoran snakes (Lycodryas), and Malagasy leaf-nosed snakes (Langaha madagascariensis).

History

This snake was first described by Thomas Nelson Annandale (the first director of the Zoological Survey of India) in 1906.

For more than 100 years, its sexually dimorphic color scheme led to confusion of the females with the brown-speckled whipsnake and the males with the long-nosed whip snake. To resolve this confusion a team of biologists conducted molecular and morphological study of this snake, ultimately finding it to be a distinct species from both the long-nosed and brown-speckled whipsnakes.

References

1. Mohapatra, Pratyush; K Dutta, Sushil; Kar, Niladri Bhusan; Das, Abhijit; Murthy, BHCK; Deepak, V (2017-05-01). "Ahaetulla nasuta anomala (Annandale, 1906) (Squamata: Colubridae), resurrected as a valid species with marked sexual dichromatism". Zootaxa. 4263: 318–332. doi:10.11646/zootaxa.4263.2.6.