Boiga whitakeri, Ganesh & Mallik & Achyuthan & Shanker & Vogel, 2021

Boiga whitakeri sp. nov.

( Fig. 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 ; Table 1 View TABLE 1 )

Material examined. Holotype. BNHS 3597 View Materials (ex. CESS 255 ) an adult male collected by SP & MP in 2011 ; Paratype. BNHS 1863 View Materials collected by K.G. Adiyodi, from Pullompara, Ernakulam dt., Kerala, in June 1961 .

Type locality. Devar Malai (9.173N, 77.261E; 1020 m asl), Tirunelveli dt., Tamil Nadu, in Periyar Plateau of the Southern Western Ghats GoogleMaps .

Etymology. Patronym named in genitive singular case honoring Romulus Whitaker, for his pioneering and substantial efforts to study and conserve Indian reptiles, especially snakes. Suggested common name: Whitaker’s cat snake.

Diagnosis. A species of Boiga occurring in the Southern Western Ghats, having 19 midbody scale rows; ventrals 235–243; subcaudals 88–98; a creamy brown dorsum with orange transverse streaks; crown with faint markings; ventrolateral pattern composed of small brown dots; phylogenetically delineated as a species, sister to B. ceylonensis of Sri Lanka (node support 98%), sufficiently divergent (5.1% at cyt b, 0.9% at 16s, 4.2% at ND4) from and closely allied to the allopatric B. ceylonensis than to any other sampled Indian or Sri Lankan congeners.

Comparisons. Boiga whitakeri sp. nov. can be distinguished from related and sympatric congeners as follows: 19 midbody dorsal scale rows (vs. 21–23 in B. nuchalis , B. dightoni ); a dorsal color that is creamy yellow with orange streaks vs. (greyish brown body with dark brown bars in B. ceylonensis ; yellowish-brown dorsal color with black patterns in B. thackerayi ; green or greenish in B. flaviviridis ; yellowish ground color with black bands in B. beddomei ); subcaudals <100 (vs.> 110 in B. beddomei , B. flaviviridis ); crown with faint brown markings (vs. crown markings absent or obscure in B. beddomei ; crown with prominent black markings in B. ceylonensis , B. thackerayi ); ventrolateral region with small brown dots (vs. unpatterned in B. flaviviridis ; large alternating white and black blotches in B. thackerayi , B. barnesii ); head, neck and body cream-colored with orange streaks throughout (vs. head and neck yellowish-brown, interscalar skin yellowish-brown with distinct black crossbars and markings in B. thackerayi , body pale brownish, with blackish-brown crossbars and pattern in B. ceylonensis ).

Description of the holotype. Holotype coiled, hemipenis everted, ventral region of the mid body incised for tissue.A medium-sized snake measuring 645 mm total length, snout-vent length: 500 mm, tail length: 145 mm, relative tail size 22.4%; vertical eye diameter: 3.3 mm, horizontal eye diameter: 3.7 mm; head length: 16.4 mm; eye to nostril distance: 2.6 mm; eye to lip distance: 1 mm; body with slender habitus, thin neck 3.88 mm at nape, wide head 8.44 mm at the angle of the jaw; head relatively longer with HL 19.54 mm, HW/HL ratio 41.9%; tail long (22.4%); dorsal scale rows 19:19:17; rostral visible from above; preocular 1, subequal to loreal; postoculars 2 on both sides; loreal 1 on both sides; supralabials 8/8, with 3 rd, 4 th and 5 th supralabials touching eye on both sides, 6 th supralabial being the largest; infralabials 11/12, 1–3 touching the first genials and 4–6 touching the second genials; temporals 10 on both sides; prefrontal in contact with the preocular; a pair of prefrontals that are in contact with the nasals, prefrontal length 2.2mm; sub-triangular frontal of length 4.3 mm; nasal divided, posterior part of the nasal in contact with the prefrontal and the first and second supralabial and the loreal, preventrals 2; ventrals 235, angulate laterally; anal scale entire; subcaudals 98 pairs. Dorsal color cream to light brown (in life), rather uniform throughout the dorsum; except in parts of labials and coastal scales that were whitish; dorsum with 122 (83 on body, 39 on tail) orange cross bars; cross bars covering 2–4 scales in size, extending on either side up to 3–4 scale rows across; interspaces often with sparse streaks; a distinct dark brown postocular stripe up to the jaw angle; labials, chin and venter light cream to dirty white. The specimen in preservative faded into a light grey dorsally with slightly darker markings and cross bars on the body. The dark nuchal and head markings faded; dirty white gular region and ventrum light yellow finely dotted with brown spots; head with dark markings and a dark brown distinct temporal streak extending from behind the oculars till the angle of the jaw. Holotype somewhat impacted by suboptimal preservation.

Variation shown by the paratype. Agreeing well with the holotype and showing the following intraspecific variations: snout to vent length: up to 677 mm, with tail length up to 154 mm; head length: 22 mm; head width: 14 mm; eye diameter: 4.7 mm; inter-orbital distance: 11.4 mm; anterior scale rows: 18; posterior scale rows: 15; ventrals 243; subcaudals 88; preventrals 3; supralabials 9 (4–6 touch eye); infralabials 12–13 (1–6 touch genials); dorsum with much bolder series of cross bars; a distinct horizontal cross bar on occiput; venter with small brown spots. Paratype in good condition retaining the colour pattern and habitus, without any preservation artifact.

Distribution and Natural History. The type specimen was collected in Devar Malai range or Vairavankulam Reserve Forests / Suttivezhi Vayal (Tirunelveli district, Tamil Nadu State) in the far south of Periyar plateau in the Southern Western Ghats. Devar Malai is perhaps the most inaccessible, little-known and under-surveyed hill range in the Western Ghats, owing to its remoteness, lack of roads and rugged terrain. Situated just south of Sivagiri hills and drained by the Karuppanadhi river, Devar Malai continues westwards as the Aruvappulam hills in Kerala and drops steeply eastwards to the plains at Puliyangudi. Historically, Devar Malai has been mentioned in literature as Ayen/Achen Koil hills or Chokkampatty Hills by Col. R.H. Beddome. The habitat at the type locality consists of evergreen rainforests ( Bourdillon, 1908). Beddome (1877) described these areas as “dense moist forest above the Ayen-Coil pass (Travancore), at about 2500 feet elevation”. Very little is known about the natural history of the new species, except that it is nocturnal and arboreal, like other Boiga spp. The paratype is labeled as from “Eranakulam, Pullompara”. While Eranakulam is evidently the provincial name, “Pullompara” appears to be an anglicized word that probably refers to forests near Pulluvazhy Para (10.086N, 76.511E) abutting the Thattekad or Kothamangalam Forest (10.103N, 76.701E). Other interpretations viz. Pullampara (Trivandram) or Pulayampara (Palghat) or Pollompara ( Kannur) are untenable and unassociated with the erstwhile Ernakulam Province. The collector of the paratype in 1963, “K.G. Adiyodi”, refers to Dr. Kenoth Govindan Adiyodi (1938–2001), a Zoology Professor who worked at various institutions in Kerala (Anilkumar et al. 2010). In June 2008, one of us (NSA) recorded a live Boiga having 19 midbody scale rows and lacking white ventrolateral blotches, from Courtallam (8.929N, 77.237E; 630 m asl), Tirunelveli district, Tamil Nadu, just 30 ariline km south off the type locality. The snake was seen coiled and resting inside a tree hole during daytime, in hilly evergreen forest tracts. Thus, at the type locality and elsewhere within its known distribution range, the new species is sympatric with B. nuchalis and B. thackerayi judging by our previous excursions in Devar Malai and nearby ranges (NSA, SRG pers. obs.). Presumably nocturnal and arboreal.