Ahaetulla malabarica, 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 : 30-34

Ahaetulla malabarica sp. nov.

Dryophis mycterizans (not of Linnaeus, 1758)— Wall, 1919: 572

Ahaetulla nasuta (not of Lacépède, 1789)— Hutton & David, 2009: 305 [part]

Holotype. BNHS 3586 ( CESS090 ); adult male; Thirunelli forest , Brahmagiri, Wayanad, Kerala; Coll. Ashok Kumar Mallik, 2010.

Paratypes. BNHS 3587 ( CESS087 ) ; adult female; Kalpetta, Kerala, Coll. Saunak P. Pal, S. P. Vijayakumar & Mrugank Prabhu, 2010 .

Other referred material. CESS 088; adult female; Kalpetta, Kerala; Coll. Saunak P. Pal, S. P. Vijayakumar & Mrugank Prabhu, 2010.

CESS 089; adult female; Kurichiyarmala, Kalpetta, Kerala; Coll. Ashok Kumar Mallik, 2010.

CESS 311; adult female; Iruppu, Coorg, Karnataka; Coll. Saunak P. Pal, 2012.

CESS 143; adult female; Silent valley, Kerala; Coll. Saunak P. Pal, 2010.

CESS 144; juvenile; Silent valley, Kerala; Coll. Saunak P. Pal, 2010.

CESS 114; adult female; Siruvani, Silent valley national park, Kerala; Coll. Saunak P. Pal, 2010.

Type locality. Thirunelli forest (11.9172 N 75.99111E, 960 msl), Brahmagiri-Wayanad hill complex of the Central Western Ghats, in Peninsular India .

Etymology. Latin, for an inhabitant of Malabar (a historical name given for provinces in North Kerala), in allusion to its distribution in that part of the Western Ghats, just north of the Palghat Gap.

Diagnosis.

1. Ahaetulla malabarica sp. nov. (L6) is nested within a clade comprising four new lineages from the Western Ghats (including L3, L4 & L5) and A. nasuta (L2) from Sri Lanka. Ahaetulla malabarica sp. nov. is genetically sister (with 70%<bootstrap support) to the new lineages A. farnsworthi sp. nov. (L4) and A. isabellina comb. nov. (L5).

2. There is a low level (3.5 % in Cytb and 1.1 % in 16S) of genetic divergence from A. isabellina comb. nov. (from Southern Western Ghats), but they are separated by Palghat Gap. It shows a moderate level (4.6 % in Cytb and 1.9 % in 16S) of genetic divergence from the A. farnsworthi sp. nov., which is distributed closer to its range.

3. A species of Ahaetulla characterised by a short rostral appendage (vs. long in A. oxyrhyncha comb. nov.; A. laudankia ; vs. multi-scaled rostral appendage in A. pulverulenta , A. sahyadrensis nom. nov., A. anomala ); possessing white ventrolateral stripe (vs. lacking in A. pulverulenta , A. sahyadrensis nom. nov.); possessing 6 prediastemal and 7 postdiastemal maxillary teeth (vs. 7 and 9 in A. isabellina comb. nov. vs. 6 and 11 in A. farnsworthi sp. nov., vs. 6 and 8 in A. borealis sp. nov., vs. 7 and 7 in A. oxyrhyncha comb. nov.). At higher elevations of the Nilgiri hill complex, this species differs from the potentially allopatric congener A. perroteti by possessing 167–183 ventrals (vs. 136–146 in A. perroteti ), 124–155 subcaudals (vs. 70–86 in A. perroteti ) and usually green body, sometimes polymorphic in colouration in both sexes (vs. usually grey-brown in A. sahyadrensis nom. nov.; adult females brownish in A. dispar and A. perroteti ) ( Fig. 15 , Table 2 ).

4. The species is distributed at the southern tip (Nilgiri hills) of the Central Western Ghats. Currently, it is known to be found from Elivalmalai to Brahmagiri hills and separated by a small gap at Tadiyendamol from A. farnsworthi sp. nov.

Description of Holotype. Adult male of total length 1074 mm; dissected; hemipenis everted; very slender, partially laterally compressed body with snout to vent length 662 mm; tail length 412 mm; relative tail length 0.38; ventrals 175 notched with keels; subcaudals 155, divided; cloacal scale divided; relatively long and slender tail; dorsal scale rows in 13-15-9 rows of smooth, obliquely disposed scales; head distinct from neck with head length 30.7 mm; transversely oval eyes with horizontal pupil, with a horizontal diameter of 5 mm and vertical diameter of 3.5 mm; distance from nostril to eye 7 mm; distance from snout tip to eye 10.7 mm; supralabials 8 (both left and right) with the 6 th supralabial being the largest, 5 th supralabial in contact with the eye; supralabial scale division on the 4 th SL; infralabials 9 (both left and right); 1 st, 2 nd, 3 rd and 4 th infralabials in contact with the anterior genials; 4 th and 5 th infralabials in contact with the posterior genials; mental scale wedged in between 1 st pair of infralabials not in contact with the genials; nasal 1 (both left and right); loreals absent; pre-suboculars 2 (both left and right); preocular 1 (both left and right); post-oculars 2 (both left and right); sub-oculars absent; temporals 2+2+3 (both left and right); prefrontal scale in contact with the pre-oculars and preventrals 2.

Colour in life. Dorsum uniform bright green; rostral, infralabials, venter bright green to lighter green in mid body; some infralabials with small white patches; yellow ventral stripe along notched ventral keels from a few scale rows after the nape; slight discolouration in the pre-ocular; inter-scalar white with black and white anteriorly-converging bars, white becoming uniform pinkish posteriorly; golden yellow eyes 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 and subcaudals green.

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

Variation shown by paratype and other referred material. In general, agreeing with the holotype and showing the following intraspecific variations: ventrals 167–183, notched with keels; subcaudals (males)—155, divided, 124–152 (females), divided; dorsal scale rows in 15-15–13/11/9 rows of smooth, obliquely disposed scales; supralabials 8–9 with either 5 th or 6 th supralabial being the largest; 5 th supralabial in contact with the eye; supralabial scale division on the 4 th supralabial; infralabials 8–9; pre-suboculars 1–2; 1 pre-ocular (both left and right); post-oculars 2; sub-oculars absent; temporals 1+2 or 2+2; some specimens have a pronounced rostral appendage with scale divisions (1–2) or bumps on it. Apart from the aforementioned colour form, this species occurs in other colour morphs: dorsum sunset yellow to light bronzy brown; rostral, infralabials, venter turmeric yellow to light brown; feeble black eye stripe, from loreal till temporal, across eye, onto nape; sometimes a yellow or white ventral stripe along the 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.

Maxillary arch dentition (dissected from CESS114). Mildly arched with a dip towards maxillary diastema; 14 teeth perpendicular to maxilla, curving inwards; prediastemal teeth 6, postdiastemal teeth 7, observable gradual tooth size increase in prediastemal tooth set with the largest teeth precursing diastema; diastema 3 tooth-socket gaps wide; suffixed with a set of 5 small teeth, almost uniformly sized followed by last grooved pair of large teeth ( Fig. 6c ).

Hemipenis (everted). Dissected; organ short (6.1 mm long) and thick (5.8 mm wide), extending upto 2–3 subcaudal scales; organ unilobed, bulbous, topped with a large globular lobe head and a short and thick pedicel; lobe head heavily beset with spiny flounces; distal and dorsal parts of lobe with smaller erect spines, while mid and proximal parts of lobe have longer cursive spines; in asulcate view, flounces fully covering the pedicel; in sulcate view, sulcus spermaticus mildly visible as a groove; centripetal, seemingly coiling towards right.

Distribution and Habitat. This species is distributed in the Western Ghats, north of the Palghat gap to Tadiyendamol in Karnataka, in mid-elevation evergreen forests from ~650 to 1400 msl ( Fig. 16 ).

Figures

FIGURE 6. Ahaetulla lineages in Peninsular India and Sri Lanka showing side-by-side comparison of their superficial head morphology and maxillary dentition. (From the top) (a) Ahaetulla farnsworthi sp. nov. (b) A. isabellina comb. nov. (c) A. malabarica sp. nov. (d) A. borealis sp. nov. (e) A. nasuta (f) A. oxyrhyncha comb. nov. (g) A. sahyadrensis nom. nov. (h) A. travancorica sp. nov. (i) A. dispar & A. travancorica sp. nov. (j) A. perroteti (1) Ahaetulla farnsworthi sp. nov. (2) A. isabellina comb. nov. (3) A. malabarica sp. nov. (4) A. borealis sp. nov. (5) A. nasuta (6) A. oxyrhyncha comb. nov. (7) A. pulverulenta (8) A. sahyadrensis nom. nov. (9) A. dispar (10) A. travancorica sp. nov. (11) A. perroteti.

FIGURE 15. Images of Ahaetulla malabarica sp. nov. Images of Holotype BNHS 3586 (CESS090). (a) Head lateral, (b) Head dorsal, (c) Ventral section, (d–f) Everted Hemipenis. Whole specimen (CESS090). Head lateral images of different colour morphs (live), (g) CESS090 from Brahmagiri, (h) CESS144 from Siruvani, (i) CESS143 from Poochipara, (j) CESS090 from Brahmagiri. Image of a live, uncollected individual, (k) Whole animal from Brahmagiri Hills (Images a & b; d & e to scale, other images not to scale).

FIGURE 16. Habitat of Ahaetulla malabarica sp. nov. in Brahmagiri Hills, Central Western Ghats (borders Kodagu district, Karnataka State and Waynad district, Kerala State, India) showing semi-evergreen and evergreen forest vegetation types.