Ahaetulla borealis, Mallik & Srikanthan & Pal & D’Souza & Shanker & Ganesh, 2020

Mallik, Ashok Kumar, Srikanthan, Achyuthan N., Pal, Saunak P., D’Souza, Princia Margaret, Shanker, Kartik & Ganesh, Sumaithangi Rajagopalan, 2020, 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), pp. 1-62 : 37-39

publication ID	https://doi.org/ 10.11646/zootaxa.4874.1.1
publication LSID	lsid:zoobank.org:pub:8FF98990-0E47-4BB7-82BB-098F86771271
DOI	https://doi.org/10.5281/zenodo.4567195
persistent identifier	https://treatment.plazi.org/id/353C523C-1423-261C-FF50-9414FEA1FB5B
treatment provided by	Plazi
scientific name	Ahaetulla borealis
status	sp. nov.

Treatment

Ahaetulla borealis sp. nov.

Dryophis nasutus (not of Lacépède, 1789)— Sharma, 1976: 163

Holotype. BNHS 3590 View Materials ( CESS421 ); adult male; Castlerock, Karnataka; Coll. Saunak P. Pal and S. R. Chandramouli, 2012.

Paratype. BNHS 3591 View Materials ( CESS104 ) ; adult female; Matheran, Maharashtra; Coll. Ashok Kumar Mallik, 2010 .

Other referred material. CESS 103; adult male; Matheran, Maharashtra; Coll. Ashok Kumar Mallik, 2010.

CESS 422; adult male; Yana, Devimane Ghat; Coll. Saunak P. Pal and S. R. Chandramouli, 2012.

Type locality. Castlerock (15.397 N, 74.342 E, 670 msl) in the Northern Western Ghats, Uttara Canara district , Karnataka GoogleMaps .

Etymology. Latin, adjective termed after the ‘boreal’ or northern parts of a region, referring to its distribution in the Northern Western Ghats.

Diagnosis.

1. Ahaetulla borealis sp. nov. (L3) is phylogenetically nested within the clade comprising new lineages of Ahaetulla (L4, L5 and L6) from the Western Ghats and Sri Lanka. It shares common ancestry with the clade (>70%) comprising A. farnsworthi sp. nov., A. malabarica sp. nov., and A. isabellina comb. nov.

2. It is separated from the clade comprising A. farnsworthi sp. nov., A. malabarica sp. nov., and A. isabellina comb. nov. with a moderate level (4.7% in ND4, 4.5–5.4% in Cytb and 1.5–1.7% in 16S) of genetic diver-gence.

3. A species of Ahaetulla having a short rostral appendage (vs. long in A. oxyrhyncha comb. nov., A. anomala , A. laudankia ), characterised by possessing 6 prediastemal and 8 postdiastemal maxillary teeth (vs. 7 and 9 in A. isabellina comb. nov., 6 and 11 in A. farnsworthi sp. nov., 6 and 7 in A. malabarica sp. nov. and 7 and 7 in A. oxyrhyncha comb. nov.); usually green coloured body in both sexes (vs. usually grey-brown in A. sahyadrensis nom. nov., adult females brownish in A. anomala , A. dispar and A. perroteti ) ( Fig. 19 View FIGURE 19 , Table 2).

4. Ahaetulla borealis sp. nov. is distributed in the Northern Western Ghats. It is flanked by A. farnsworthi sp. nov. to the south of its distribution range, from which it is isolated presumably by the Sharavathi river basin that lies between the northern fringe of Kodachadri and southern fringe of Devimane-Sirsi range. We found that this species occupies a large range despite relatively sparse sampling in the Northern Western Ghats.

Description of the Holotype. Adult of total length 1067 mm; hemipenis dissected; very slender, partially laterally compressed body with snout to vent length 592 mm; tail length 434 mm; relative tail length 0.41; ventrals 180 notched with keels; subcaudals 157 divided; cloacal scale divided; relatively long and slender tail; dorsal scale rows in 15-15-13 rows of smooth, obliquely disposed scales; head very distinct from neck with head length 28.6 mm; transversely oval eyes with horizontal pupil, with a horizontal diameter of 4.4 mm and vertical diameter of 3.3 mm; distance from nostril to eye 6.6 mm; distance from snout tip to eye 9.8 mm; supralabials 8 (both left and right) with 6 th supralabial being the largest, 5 th supralabial in contact with the eye; 4 th supralabial divided; infralabials 9 (both left and right), 1 st, 2 nd, 3 rd and 4 th infralabials in contact with anterior genials; 4 th and 5 th infralabials in contact with posterior genials; mental scale wedged between 1 st pair of infralabials, not in contact with genials; nasal scale 1 (both left and right); loreals absent; pre-suboculars 2 (both left and right); pre-ocular 1 (both left and right); postoculars 2 (both left and right); sub-oculars absent; temporal 2+2+2 (both left and right); prefrontal scale in contact with pre-oculars; preventral 1.

Colour in life. Dorsum uniform olive green to light green; scales bordered with brown; rostral, infralabials, venter yellowish green to light green at mid body; yellow ventral stripe along notched ventral keels; slight discolouration in the pre-ocular; inter-scalar skin white with black and white anteriorly-converging bars, white replaced by grey skin posteriorly; eyes golden yellow with black speckles; concentration of black speckles both in the anterior and posterior ends of a horizontal pupil and a slight discolouration around the pupil; tail, subcaudals green.

Colour in preservative. Dorsum non-uniform olive green to light green; rostral, infralabials, venter yellowish green to white; yellow ventral stripe along notched ventral keels; slight discolouration in the pre-ocular; inter-scalar skin white with black and white anteriorly-converging bars; eyes yellow clouded with white, with black speckles concentrated both in the anterior and posterior ends of a dilated pupil.

Variations shown by paratype and other referred material. In general, agreeing with the holotype and showing the following intraspecific variations: ventrals 174–181, notched with keels; subcaudals (males) 145–157, divided, (females) 142–151, divided; dorsal scale rows in 15-15–13/11 rows of smooth, obliquely disposed scales; supralabials 8–9 with 6 th supralabial being the largest; 5 th supralabial in contact with the eye; 4 th supralabial divided; loreal absent, (loreal 1 in CESS103), infralabials 8–9; pre-suboculars 1–2; pre-ocular 1 (both left and right); postoculars 2–3; sub-oculars absent; temporals 2+2 or 2+3; some specimens have a pronounced rostral appendage with scale divisions (1–2) or bumps on it.

Hemipenis (everted). Organ comparatively longer (6.8 mm long) with a medium width (5.4 mm wide); extending upto 3 to 4 subcaudal scales; unilobed, lobe head wide (5.4 mm), pedicel not quite narrow (pedicel length ~ 4 mm), covered up by flounces that are shorter on the top aspect and cursive and longer on the lateral aspect; length of largest spine 1.1 mm; flounces appear cramped and clustered, probably a preservation artefact; spines on top of lobe head short and erect; in asulcate view, spiny flounces totally cover the pedicel; in sulcate view, sulcus spermaticus appears like a furrow, apparently centripetal, turning to the right.

Maxillary arch dentition (dissected from CESS103). Mildly arched at anterior tip of maxilla, a slight dip towards maxillary diastema; 14 teeth perpendicular to maxilla, curving inwards; prediastemal teeth 6, postdiastemal teeth 8, observable gradual tooth size increase in prediastemal tooth set with the largest teeth precursing diastema; diastema 3.5–4 tooth-sockets wide; suffixed with a set of 6 smaller teeth almost uniform in size followed by the last grooved pair of large teeth ( Fig. 6d View FIGURE 6 ).

Variations in colour morphs. Dorsum bright green with blue patches; a gradual reduction of blue patches from later, more prominent in lateral sides; scales on head sometimes with dark blue dots bordered with light blue; rostral, infralabials, venter at midbody light green to light blue; sometimes a yellow ventral stripe along notched ventral keels; inter-scalar skin white with black and white anteriorly-converging bars; eye yellow to orange with light brown marbled patterns; horizontal pupil with a light blue or yellow colouration around the pupil; tail, subcaudals green.

Distribution and Habitat. This species was recorded in the Northern Western Ghats, from Devimane Ghats (=Sirsi hills) in Karnataka to Matheran in Maharashtra, across nearly 600 km ( Fig. 20 View FIGURE 20 ). This species occurs in low to mid-elevation moist deciduous and semi-evergreen forests from ~300 to 750 msl. This is one of the most widespread members of the genus within the Western Ghats, surpassed only by A. sahyadrensis nom. nov. which belongs to a different clade.