Trimeresurus salazar Mirza, Bhosale, Phansalkar, Sawant, Gowande & Patel, 2020

Vogel, Gernot, Mallik, Ashok Kumar, Chandramouli, S. R., Sharma, Vivek & Ganesh, S. R., 2022, A review of records of the Trimeresurus albolabris Gray, 1842 group from the Indian subcontinent: expanded description and range extension of Trimeresurus salazar, redescription of Trimeresurus septentrionalis and rediscovery of historical specimens of Trimeresurus davidi (Reptilia: Viperidae), Zootaxa 5175 (3), pp. 343-366 : 349-354

Trimeresurus salazar Mirza, Bhosale, Phansalkar, Sawant, Gowande & Patel, 2020

( Figures 1 – 6 ; Table 2 )

Trimeresurus albolabris — Pope & Pope 1933 (part); Smith 1943 (part)

Trimeresurus albolabris albolabis — Kramer, 1977 (part); Regenass & Kramer, 1981 (part)

Trimeresurus albolabris — Giannasi et al. 2001 (part); Gumprecht et al. (part)

Trimeresurus albolabris — Das 2002; Whitaker & Captain 2004; Ahmed et al. 2009

Specimens Examined (n = 4). Males: India: BMNH 72.4 .17.379 along the Darjeeling slopes (27.041˚N 88.266˚E, 210 m) in the Eastern Himalaya West Bengal ; CESS 604 , Aizwal , Mizoram . Females: India: BMNH 1937.3 .1.14 Nagpur, Central Province India, exact location unknown (see below); BMNH 1908.6 .23.99 Assam . Tissue samples sequenced: India: CESS535 from Jashpur, Chhatisgarh; CESS331 from Byrnihat , Meghalaya .

Description and Variation (based on examined specimens). Body moderately elongate, slender; head elongate, triangular, flattened, broadest width occurs from eyes to end of the head just before the starting of neck, over twice as long as broad, clearly distinct from neck; snout moderate, overall flattened from top and side view, rounded from top view, truncate when seen from lateral side, one third of total head length, twice as long as diameter of eye, canthus rostralis distinct; eye moderate; tail typically cylindrical in cross section fairly short, prehensile, tapering. SVL: 459–565 mm; TaL: 92–116 mm; TL: 571–659 mm; HL: 21.01–26.93 mm, HW 10.05–16.34 mm; ratio TaL/TL: 0.193 –0.196 in males and 0.143 –0.152 in females; VEN: 163–170; PV 2–3; SC: 62–73 pairs in males, 56–59 pairs in females; anal entire. DSR: 19–23:21:15–17 scales, rhomboid, moderately keeled, first row smooth. Rostral visible from above, one and a half times broader than high, triangular; nasal+first supralabial pentagonal, about as broad as high, undivided, nostril in the middle; one pair of enlarged internasals, in good contact with each other, slightly broader than long, about 4 times larger than adjacent upper snout scales; canthal scales between the internasal and corresponding supraocular, slightly larger than adjacent snout scales; 1 triangular loreal between lower preocular and second supralabial; two upper preoculars above the loreal pit, elongated, lower in contact with the loreal; lower preocular forms posterior - upper margin of loreal pit; 2/2 postoculars; 1 large, entire, long and narrow supraocular on each side; supraocular lightly indented on their inner margin by the upper head scales; scales on upper snout surface smooth, juxtaposed, irregular in shape, moderately but distinctly enlarged, typically looking like a juxtaposition of irregular paving stones; only 3 snout scales between internasals and supraoculars; cephalic and occipital scales smaller, irregular, juxtaposed, smooth and flat on upper head surface, scales confined on middle and occipital area slightly smaller than snout scales; temporal scales larger than cephalic and occipital scales, lightly swollen but not keeled; 10–12 cephalic scales in a line between supraoculars; 10/11 SL; 1st SL completely fused with nasal, forms irregular pentagonal shape, about as broad as high; 2nd SL high, slightly shorter than nasal+1 SL, forms the anterior border of loreal pit, 3rd SL largest, longest of all, about twice as long as 2nd SL, longer than high, in contact with the subocular; 4th SL distinctly shorter, more than 2/3 times as high as 3rd one, 5th and other posterior SL slightly smaller than 4th; both 4th and 5th SL separated from the subocular by one scale row, others in contact with the first lowest row of temporals; 11/13 IL, first pair in contact with each other behind mental, the first three pairs in contact with the anterior chin shields; 4/4+1 smooth gular scales; posterior chin shields nearly half of anterior chin shields. In life, green or yellowish green to yellow above. In preservative, the upper and lateral body surfaces uniformly dark brown or bluish. Ventrolateral stripe distinct; off - white or yellow (CESS535) in colour; the stripes largely restricted to last row of dorsal scales, not extending on to the edges of ventral scales. Ventral scales predominantly yellow and often outlined with dark brown. Upper and lower lip as yellowish as underside. A dark brown eye streak of about one scale breadth passing from upper of 2nd SL, upper of 3rd SL to scale row below suture to last 4 SL and finally forms the dark ventrolateral line below yellow - white line. More than half of tail rusty red which gradually turns darker towards tip. Eyes with greenish yellow iris and black vertically elliptical pupil. Tongue blackish pink, with tips slightly darker.

Remarks. Compared to the recent original description ( Mirza et al. 2020), our sample size has increased (4 in Mirza et al. 2020 and 4 more in this work). The original description ( Mirza et al. 2020) states some specimens as having 19 midbody scale rows, but in our study, that was not the case. All snakes consistently had 21 midbody scale rows. Anterior scale rows varied as 19–23. Rathee et al. (2021) also reported 21 rows for the Meghalaya specimens. In the original description, the relative tail lengths were 18% (males), 14% (females); our new data has expanded these values to up to 19% in males and 15% in females. The original description states that ventral scales in T. salazar range from 163–171, and that subcaudals range from 59–74 (sexes pooled). Rathee et al. (2021) reported the counts as 164–170 and 68–70 respectively. In our series of specimens, the corresponding ranges were 163–170 and 56–73, falling within the reported range ( Mirza et al. 2020; Rathee et al. 2021) and showing consistent values. Between sexes, the subcaudal counts of males were as low as 62. Our specimens were also larger in length, TL: 659 mm (SVL 565 + TaL 94 mm) whereas it was 509 mm (SVL 415 + TaL 94) in Mirza et al. (2020) and comparable to the Meghalaya specimens 655–660 mm (SVL 555–560 + TaL 100–105; fide Rathee et al. 2021). Thus, our new morphological data, though consistent with the original description, is slightly outranging and expands the morphological characterization of this species.

Distribution and Habitat. Based on our new specimens and field observations, Trimereusrus salazar occurs as far west as Kanha National Park (22.334˚ N 80.611 ˚E 570 m), in the Seoni Hills and in Jashpur (22.875˚ N 84.137 ˚E 780 m) in the Chota Nagpur Plateau. In the north, it was found in northeast India along the Darjeeling slopes (27.041˚ N 88.266 ˚E, 210 m) and in the Eastern Himalaya, close to its type locality (26.968˚ N 93.013 ˚E, 172 m). In the east, it occurs near the Myanmar border abutting the Patkai hills (27.759N, 96.000˚E). Thus, judging by its current records, we hypothesize that T. salazar is distributed over a large swath of the wet forest belt of Central India and in the Chota Nagpur plateau, through the Siwalik ranges and eastwards onto the Patkai hills near the Myanmar border. More arid regions such as the Gwalior plateau to the west, the Himalayas in the north, the Patkai hills in the east and the Mahanadi River in the south (west) may act as barriers to its distribution. It is possible that the location of the name ‘Nagpur’ (Eastern Maharashtra) as associated with the label of the BMNH specimen might refer to ‘Chota Nagpur’ (Jharkhand–Bihar–Odisha), a much more northeasterly region (VS pers. obs.). However, the presence of T. salazar in the nearby Kanha National Park and the phrase ‘Central Province’, implies that ‘Nagpur’ might refer to the Seoni hills in the erstwhile boundaries of region. We also state here that the closest location to ‘Nagpur’ where T. salazar is expected to occur is in Bhander Forest Range (21.511˚N, 79.408˚E), 70 airline km north and then Gadchiroli Forest (20.115˚N, 80.076˚E), 150 airline km southeast.

One of us (VS) conducted fieldwork in Chattisgarh, Central India during May–September 2013 and recorded two sightings of T. salazar in subtropical seasonal woodlands and modified plantations abutting rural gardens. In most of the parts of its range, T. salazar has been repeatedly found around human settlements even in places where vegetation is much more restricted and disturbed. It prefers to stay at low to moderate heights in dense and low bushes, shrubs, and trees. Overall, judging by verified photographic records shared by colleagues, T. salazar appears to be continuously distributed from central - southern Nepal, from Kanha National Park of central India (in Madhya Pradesh) to Chota Nagpur Plateau (Chattisgarh), eastwards to Jharkhand, Bihar, northeast states of (northern) West Bengal, Sikkim, southern Bhutan, Meghalaya, Assam, Arunachal Pradesh, Nagaland, and Mizoram (see Discussion for Bhutan and Nepal records in literature). One of our localities—Kanha (Madhya Pradesh) is 250 airline km east off the historical record Nagpur (Maharashtra). Sympatric congeners recorded include T. gramineus in the Central Indian and Chota Nagpur regions and T. erythrurus in the Indo - Burmese regions in northeast India (see below).

Figures

FIGURE 1. Map of the Indian subcontinent showing newly recorded / identified distribution records of (i). Trimeresurus salazar (black; field records: squares, specimen records: dots); (ii). T. septentrionalis (white); type localities with a dot in the middle (iii). T. davidi (encircled—corrected locality / X—incorrect locality)

FIGURE 2. Reconstructed phylogeny from three concatenated mitochondrial genes showing the phylogenetic position of T. salazar nested within the clade comprising other members of T. albolabris species complex. The values on nodes show the posterior probability from Bayesian inference and bootstrap values from the maximum likelihood analysis.

FIGURE 3. Trimeresurus salazar live uncollected subadult males from Jashpur, India. Photos: Vivek Sharma

FIGURE 4. Trimeresurus salazar live uncollected adult females from Jashpur and Bilaspur (Kanan Pendari Zoo) India. Photos: Vivek Sharma

FIGURE 5. Trimeresurus salazar live adult males showing intraspecific variation in the intensity of red lateral striping—top: individual with bold and thick red stripe from Byrnihat, Meghalaya (Photos: Ashok K. Mallik); above: individual with obscure and thin red stripe from Kanha, Madhya Pradesh. (Photo: Yajuvendra Upadhyaya).

FIGURE 6. Trimeresurus salazar NHMUK 1937.3.1.14 from ‘Nagpur, Central Province’, India. Photos: Gernot Vogel