Ahaetulla anomala ANNANDALE, 1906
Can you confirm these amateur observations of Ahaetulla anomala?
|Higher Taxa||Colubridae, Ahaetuliinae, Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Synonym||Dryophis mycterizans var. anomalus ANNANDALE 1906|
Dryophis mycterizans lepidorostralis WALL 1908 (fide SMITH 1943)
Dryophis mycterizans lepidorostralis WALL 1910 [nomen nudum fide Wall 1910]
Passerita purpurascens — ANDERSON 1871 [in part]
Ahaetulla pulverulenta — DASGUPTA & RAHA 2004
Ahaetulla pulverulenta — DENZAU & DENZAU 2010
Ahaetulla anomala — MOHAPATRA et al 2017
Type locality: Santragachi, Howrah district, West Bengal, India
|Reproduction||ovoviviparous (5-15 live offspring)|
|Diagnosis||Diagnosis. Ahaetulla anomala has characters of the rear-fanged genus Ahaetulla (Smith 1943). Its prominent, longer dermal appendage distinguishes it from other species of Ahaetulla found in India and Sri Lanka except A. nasuta and A. pulverulenta. Morphologically A. anomala differs from all forms of A.nasuta in having its dermal appendage covered by many small scales above (vs. dermal appendage formed by rostral scale only); it has a dark rhomboidal pattern on the dorsal surface of the head (vs. no dorsal head marking); in A. anomala the asulcate side of hemipenis has 3–5 nude grooves (vs. 5–7 in A. nasuta Odisha population).|
Though the brown colour forms (adult females) of A. anomala are superficially similar to A. pulverulenta, it differs from the latter in: length of dermal appendage shorter than horizontal eye diameter (vs. always longer in adults); sexual dichromatism- body colouration of adult males are green and females brown (vs. always brown or greyish- brown); dorsal scales at one head length before vent – 11 rows, rarely 13 in females and 9 in males (vs. mostly in 13 rows). The hemipenis of A. anomala also differs in structure from that of A. pulverulenta (Western Ghats specimens) in bearing 5–6 large spines on the asulcate side (vs. 8–9 large spines) [MOHAPATRA et al 2017]
|Comment||Synonymy: after Mohapatra et al. 2017. Dryophis mycterizans var. anomalus has been listed as a synonym of Ahaetulla nasuta, e.g. by Wallach et al. 2014: 20. Passerita purpurascens Günther, 1864 is a junior synonym of Ahaetulla pulverulenta (see Theobald 1868, 1876 & Anderson 1871, Mohapatra et al. 2017).|
Sexual dichromatism. Various authors have mentioned about polymorphism in ground colour in snakes such as Boiga forsteni, Sonora semiannulata and Psammophis schokari (Mohapatra et al. 2009; Cox 2012; Hussain & Hussain 2013). In a recent publication, Cox and Chippindale (2014) suggested that despite dramatic color polymorphism in Sonora semiannulata, phenotypic diversity is not a major driver of genetic diversity within or among populations. Similarly Ahaetulla anomala shows colour polymorphism and has a gradient of green and brown colours. As stated earlier, adult males of this species are green coloured and adult females are brown in colour. Among the specimens examined, the greyish-green coloured individual is a juvenile male and the greyish brown individual is a juvenile female. These intermediate colours could be an artefact of ontogenic colour change (See Deepak et al. 2010). Sexual dichromatism is rare among snakes and until now documented in some groups such as vipers (Vipera, Bothrops) (Shine & Madsen 1994; Lindell & Forsman 1996; Marques & Sazima 2003; de Freitas et al. 2014), Comoran snake (Lycodryas) (Hawlitschek et al. 2012) and Malagasy leaf-nosed snakes Langaha madagascariensis (Krysko 2003). Ahaetulla anomala is therefore the first report of sexually dichromatic snake from the Indian subcontinent [MOHAPATRA et al 2017].
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