''Ahaetulla nasuta'', also known as Sri Lankan green vine snake and long-nosed whip snake, is a venomous, slender green tree

snake Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more j ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to Sri Lanka.

Distribution

Due to longstanding confusion over the taxonomy of ''A. nasuta'', the species was once thought to have a large range from Sri Lanka to peninsular India, including the Western Ghats, along with a disjunct population in

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainlan ...

. However, a 2020 phylogenetic study found ''A. nasuta'' to actually comprise a

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

, with the "true" ''A. nasuta'' (from which the species was originally described) being restricted to the wet zone of Sri Lanka (including the Sri Lanka lowland and montane rainforests). 4 populations from the Western Ghats of India that were formerly grouped with ''A. nasuta'' were split into the species '' A. borealis'', '' A. farnsworthi'', '' A. isabellina'', and '' A. malabarica''. The large-bodied form from lowland peninsular India (and possibly the dry zone of the northern portion of Sri Lanka), which was also formerly grouped with ''A. nasuta'', was found to actually be '' A. oxyrhyncha'', and is actually more closely allied with '' A. pulverulenta'' and '' A. sahyadrensis'' than ''A. nasuta''. Finally, the disjunct population in Southeast Asia was assigned to an as-of-yet

undescribed species In taxonomy, an undescribed taxon is a taxon (for example, a species) that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and named. U ...

, tentatively referred to as ''Ahaetulla'' cf. ''fusca'', and is a sister species to ''

Ahaetulla laudankia ''Ahaetulla laudankia'', known as the Laudankia vine snake, is a species of snake in the family Colubridae. It is Endemism, endemic to India and while being a rare species, it has a relatively large range, extending from the Eastern Ghats through ...

''.

Description

Common vine snakes are diurnal,

arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose nu ...

, and mildly

venomous Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

. They normally feed on

frog A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...

s and lizards using their

binocular vision In biology, binocular vision is a type of vision in which an animal has two eyes capable of facing the same direction to perceive a single three-dimensional image of its surroundings. Binocular vision does not typically refer to vision where an ...

to hunt. They are slow moving, relying on camouflaging themselves as vines in foliage. They expand their bodies when disturbed to show a black and white scale marking. Also, they may open their mouths in a threat display and point their heads in the direction of the perceived threat. They are the only species of snake with horizontal pupils, compared to the normal vertical slit pupils found in many species of viper. The species is

viviparous Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the ...

, giving birth to young that grow within the body of the mother, enclosed within the egg membrane. They may be capable of delayed

fertilization Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...

; (

parthenogenesis Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and developmen ...

is rare but not unknown in snakes) as a female in the London zoo kept in isolation from August, 1885 gave birth in August, 1888.

Taxonomic description

The species name ''Ahaetulla'' in Sinhala means 'eye plucker'. It earned this name, and similar ones in Tamil and Indian vernaculars, due to the mistaken belief that it strikes at the eyes. The following description with diagnostic characters is from Boulenger (1890): Formerly treated as a subspecies ''Ahaetulla nasuta anomala'' is now regarded as a distinct species, '' Ahaetulla anomala''.

Habitat

Found in low bushes, shrubs and trees in lowland forest terrain at elevations up to about 1000 metres, particularly near streams and often found near human settlements.

Venom and its effects

The ingredients of the venom are unknown. The venom is moderately potent and can cause swelling, pain, bruising, numbness and other local symptoms, which will subside within three days. Bites close to the head, eyes and other vital areas could be severe. “Ahaetulla nasuta” at WCH Clinical Toxinology Resources. Accessed on 9.1.2014 at http://www.toxinology.com/fusebox.cfm?fuseaction=main.snakes.display&id=SN0004

Vernacular names

The Sinhala name "Aheatulla" or "eye-plucker" forms the taxonic species name. In

Tamil Tamil may refer to: * Tamils, an ethnic group native to India and some other parts of Asia **Sri Lankan Tamils, Tamil people native to Sri Lanka also called ilankai tamils **Tamil Malaysians, Tamil people native to Malaysia * Tamil language, nativ ...

, it is known as pachai paambu. In

Kannada Kannada (; ಕನ್ನಡ, ), originally romanised Canarese, is a Dravidian language spoken predominantly by the people of Karnataka in southwestern India, with minorities in all neighbouring states. It has around 47 million native s ...

, it is known as Hasiru Haavu. * Sinhala: ඇහැටුල්ලා (Pronounced: Aheatulla) * Tamil: பச்சை பாம்பு * Kannada: ಹಸಿರು ಹಾವು * Marathi: हरणटोळ (Pronounced: harantol)

Notes

References

* Lacepède, B. G. E. 1789 Histoire Naturelle des Quadrupèdes Ovipares et de Serpens. Vol.2. lmprimerie du Roi, Hôtel de Thou, Paris, 671 pp. * Wall, F. 1908 Remarks on some recently acquired snakes. J. Bombay N. H. S. xviii: 778-784 * Wall 1908 A new color variety of the common green whip-snake (''Dryophis mycterizans''). J. Bombay N. H. S. xviii: 919 * Wall, F. 1910 Remarks on the varieties and distribution of the common Green Whip Snake (''Dryophis mycterizans''). J. Bombay nat. Hist. Soc. 20: 229 * Wall 1910 Varieties of the common Green Whip Snake (''Dryophis mycterizans''). J. Bombay nat. Hist. Soc. 20: 524 {{Taxonbar, from=Q619087 nasuta Snakes of Asia Reptiles of Sri Lanka Endemic fauna of Sri Lanka Reptiles described in 1789 Taxa named by Bernard Germain de Lacépède