Ahaetulla nasuta
| Common vine snake | |
|---|---|
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Serpentes |
| Family: | Colubridae |
| Subfamily: | Ahaetuliinae |
| Genus: | Ahaetulla |
| Species: | A. nasuta
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| Binomial name | |
| Ahaetulla nasuta (Lacépède, 1789)
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| Synonyms | |
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Dryophis nasuta | |
Ahaetulla nasuta, also known as Sri Lankan green vine snake and long-nosed whip snake, is a venomous, slender green tree snake endemic to Sri Lanka.
Etymology
[edit]The genus name Ahaetulla comes from the Sri Lankan Sinhalese words ahaetulla/ahata gulla/as gulla, meaning “eye plucker” or “eye picker”, because of the belief that they pluck out the eyes of humans, as first reported by the Portuguese traveler João Ribeiro in 1685.[1] The species name nasuta is Latin for "of the nose", in reference to its elongated snout.[2][3]
Vernacular names
[edit]The Sinhala name "Aheatulla" or "eye-plucker" forms the taxonic genus name. In Tamil, it is known as pachai paambu. In Kannada, it is known as Hasiru Haavu.
- Sinhala: ඇහැටුල්ලා (Pronounced: Aheatulla)
- Tamil: பச்சை பாம்பு
- Kannada: ಹಸಿರು ಹಾವು
- Marathi: हरणटोळ (Pronounced: harantol)
- West Bengal: লাউডগা ( Pronounced:Laudoga)
In Western internet culture, the vine snake has occasionally been humorously nicknamed as the “judgmental shoelace”, due to their long, slender bodies and the horizontal shape of their pupils resembling a person narrowing their eyes in a captious expression.
Distribution and Taxonomy
[edit]
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. Recent phylogenetic studies have since found the species to be paraphyletic, and in need of taxonomic revision.
A 2017 study reclassified the former subspecies Ahaetulla nasuta anomala as a distinct species, Ahaetulla anomala,[4] although a 2020 study later found A. anomala to be possibly conspecific with Ahaetulla oxyrhyncha.[5]
The cladogram below from a 2019 study shows Ahaetulla nasuta as paraphyletic:[6]
| Ahaetuliinae |
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A 2020 phylogenetic study reaffirmed the paraphyletic nature of A. nasuta, and found it to actually comprise a species complex, 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). Four 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, tentatively referred to as Ahaetulla cf. fusca, and is a sister species to Ahaetulla laudankia.[5]
Habitat
[edit]It is 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.[7]
Description
[edit]Common vine snakes are diurnal, arboreal, and mildly venomous. They normally feed on frogs and lizards using their binocular vision 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.[8]
Taxonomic description
[edit]The following description with diagnostic characters is from Boulenger (1890):[9]
Snout pointed, terminating in a dermal appendage, which is shorter than the eye and formed entirely by the rostral; the length of the snout, without the appendage, about twice the diameter of the eye or rather more. No loreal; internasals and prefrontals in contact with the labials; frontal as long as its distance from the rostral or a little longer, as long as the parietals or a little longer; two preoculars and a small subocular (or one preocular and two suboculars), upper preocular in contact with the frontal; two postoculars; temporals 1+2 or 2+2; upper labials 8, fifth entering the eye; 4 lower labials in contact with the anterior chin-shields, which are shorter than the posterior. Scales in 15 rows. Ventrals 172–188; anal divided; subcaudals 140–166. Bright green or pale brownish, the interstitial skin between the scales black and white on the anterior part of the body, which appears striped when distended; a yellow line along each side of the lower surface. Total length 5 feet: tail 2.
Behavior
[edit]They feed on lizards and other invertebrates.[2] The species is ovoviviparous, giving birth to young that grow within the body of the mother, enclosed within the egg membrane. They may be capable of delayed fertilization; (parthenogenesis 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.[10]
Venom and its effects
[edit]The components of its venom are unknown.
Bites from this species produce a moderate reaction in humans, causing localized pain, swelling, bruising, and numbness that typically resolves within 72 hours. Any bite near the vital organs should be considered a medical emergency.[11][12]
References
[edit]- ^ Figueroa, A.; McKelvy, A. D.; Grismer, L. L.; Bell, C. D.; Lailvaux, S. P. (2016). "A species-level phylogeny of extant snakes with description of a new colubrid subfamily and genus". PLOS ONE. 11 (9): e0161070. Bibcode:2016PLoSO..1161070F. doi:10.1371/journal.pone.0161070. PMC 5014348. PMID 27603205.
- ^ a b Reptile Database (2016). Ahaetulla nasuta. Retrieved 16 May 2024.
- ^ Snakes of Sri Lanka Archived May 19, 2005, at the Wayback Machine
- ^ 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 (2): 318–332. doi:10.11646/zootaxa.4263.2.6. PMID 28609871. S2CID 41105263.
- ^ a b Mallik, Ashok Kumar; Srikanthan, Achyuthan N.; Pal, Saunak P.; D'souza, Princia Margaret; Shanker, Kartik; Ganesh, Sumaithangi Rajagopalan (2020-11-06). "Disentangling vines: a study of morphological crypsis and genetic divergence in vine snakes (Squamata: Colubridae: Ahaetulla) with the description of five new species from Peninsular India". Zootaxa. 4874 (1): zootaxa.4874.1.1. doi:10.11646/zootaxa.4874.1.1. ISSN 1175-5334. PMID 33311335. S2CID 228823754.
- ^ Mallik, Ashok Kumar; Achyuthan, N. Srikanthan; Ganesh, Sumaithangi R.; Pal, Saunak P.; Vijayakumar, S. P.; Shanker, Kartik (27 July 2019). "Discovery of a deeply divergent new lineage of vine snake (Colubridae: Ahaetuliinae: Proahaetulla gen. nov.) from the southern Western Ghats of Peninsular India with a revised key for Ahaetuliinae". PLOS ONE. 14 (7): e0218851. Bibcode:2019PLoSO..1418851M. doi:10.1371/journal.pone.0218851. ISSN 1932-6203. PMC 6636718. PMID 31314800.
- ^ "WCH Clinical Toxinology Resources".
- ^ Brischoux, F.; Pizzatto, L.; Shine, R. (2010). "Insights into the adaptive significance of vertical pupil shape in snakes". Journal of Evolutionary Biology. 23 (9): 1878–1885. doi:10.1111/j.1420-9101.2010.02046.x. ISSN 1420-9101. PMID 20629855. S2CID 23349083.
- ^ Boulenger, George A. 1890 The Fauna of British India, Including Ceylon and Burma. Reptilia and Batrachia. Taylor & Francis, London, xviii, 541 pp.
- ^ Wall, Frank 1905. A popular treatise on the common Indian snakes. Part 1. J. Bombay Nat. Hist. Soc. 16:533-554.
- ^ Snakes of Sri Lanka Archived May 19, 2005, at the Wayback Machine
- ^ “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
Further reading
[edit]
- 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