Trimeresurus davidi CHANDRAMOULI, CAMPBELL & VOGEL, 2020
Can you confirm these amateur observations of Trimeresurus davidi?
|Higher Taxa||Viperidae, Crotalinae, Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Synonym||Trimeresurus davidi CHANDRAMOULI, CAMPBELL & VOGEL 2020|
Trimeresurus albolabris – VIJAYAKUMAR & DAVID 2006
Trimeresurus albolabris – SMITH 1943 (part.)
Trimeresurus albolabris – VOGEL 2006 (part.)
Trimeresurus albolabris – VOGEL et al. 2014 (part.)
|Distribution||India (Car Nicobar)|
Type locality: Chuckchucka Village (9.2161°N, 92.8109°E, 14 m asl), Car Nicobar
|Types||Holotype. BNHS 3304, an adult female, collected by a group of Nicobari men (fide Vijayakumar and David 2006).|
Paratypes. DOSMB 05104, an adult male from Chuckchucka Village, Car Nicobar; NHMUK 19126.96.36.199, NHMUK 19188.8.131.52, NHMUK 19184.108.40.206, (three adult females from ‘Car Nicobar, Nicobar Is.’), NHMUK 19220.127.116.11 an unsexed adult from ‘Car Nicobar, Nicobar Is.,’ NHMUK 1918.104.22.168 and NHMUK 1922.214.171.124 (two adult males from ‘Nicobar Is.’ and ‘Andaman Is.’ [doubtful], respectively), collected during Lord Moyne’s expedition to the Nicobar Islands.
|Diagnosis||Diagnosis. Trimeresurus davidi sp. nov. is an arboreal member of the genus Trimeresurus restricted to the Car Nicobar Island of the Nicobar archipelago, characterized by: medium to large sized body (277–835 mm SVL); dorsal scales in a series of 21–25:21–23:15–17 rows; nasal partly fused with the first supralabial; 166–179 ventrals; 46–70 subcaudals; one preocular; 2–3 postoculars; 10–12 supralabials; 12–15 infralabials; two internasals usually in contact with each other; 11–14 cephalic scales; relative tail length (TaL/TL) ranging from 0.143–0.20; dorsal and ventral verdant green in color, lacking white ventrolateral stripes; males with a white supralabial streak, bordered by a reddish tinge above; a pair of white and red stripes along the sides of the tail in both males and females; a reddish brown colored tail and a greenish iris; hemipenis reaching the 13th caudal plate.|
Variation. Measurements and scale counts of the paratypes and referred material are given in Table 1. Mid-body scale rows range from 21–25:21–23:15–17; ventrals range from 170–179 in males and 166–178 in females. Subcaudals range from 67–70 in males and 55– 64 in females. Internasals usually in contact with each other, but separated by a small scale in one specimen. Cephalic scales range from 11–14; postoculars range from 2–3. Relative tail length in males: 0.178–0.200; in females: 0.143–0.161. Sexual dimorphism apparent in body for the tail dimensions and the number of subcaudals. Verdant green colored in life, both dorsally and ventrally, without a white ventrolateral pair of stripes along the sides of the body; but with a pair of white and red lateral stripes along the sides of the tail. Males have a thin white labial stripe bordered by red above the supralabials on either side of the head (absent in females) and a white stripe bordered by red along the subcaudals from the vent until about half the length of the tail (also present in females).
Comparison. Trimeresurus davidi sp. nov. does not have any superficially similar looking, green-colored arboreal congeners on Car Nicobar Island, on which its distribution is restricted. It can be distinguished from other members of the T. albolabris complex by the following combination of characters: dorsal scales of T. davidi sp. nov. in 21–25:21–23:15–17 rows (vs. 21– 23:19–21:15inT.albolabrisandT.insularis,21:21:15 in T. caudornatus, 21:19:17 in T. septentrionalis, and 21:19:15 in T. salazar). There is some overlap in this character, as is expected; however, five of the 11 (45%) examined T. davidi specimens had 23 dorsal scale rows at midbody. This character has never been recorded in any of the other species within this complex. Also, there seems to be a certain degree of overlap in scalation characters between the currently recognized members of T. albolabris complex, which makes the partially overlapping values with T. davidi sp. nov. quite understandable. Trimeresurus davidi sp. nov. has 166– 179 ventrals (vs. 149–173 in T. albolabris, 161–163 in T. caudornatus, 160–181 in T. septentrionalis, 156–167 in T. insularis, and 163–171 in T. salazar); an absence of white ventrolateral stripes along the body in T. davidi sp. nov. (vs. present in T. septentrionalis and T. salazar); and the presence of a pair of red and white ventrolateral stripes along the sides of the tail (vs. absent in all other species). Trimeresurus davidi sp. nov. is considerably larger than all other species of this complex. For further comparisons, see also the morphological characters (Table 2) for the material examined (Appendix 1) in this study.
From the two other sympatric congeners, T. andersoni Theobald, 1868 and T. labialis Fitzinger in: Steindachner, 1867, T. davidi sp. nov. can be distinguished by its verdant green dorsal coloration (vs. predominantly brown in both T. andersoni and T. labialis); midbody dorsal scales in 21–23 rows (vs. 23–25 in T. andersoni, 23 in T. labialis); and the first supralabial united with the nasal in T. davidi sp. nov. (vs. separate in T. labialis).
Additionally, from the green color morph of Trimeresurus cantori (Blyth 1846) which occurs on islands of the central group of the Nicobar archipelago, T. davidi sp. nov. can be distinguished by a lower number of mid-body scale rows (21–23 in T. davidi sp. nov. vs. 25–29 in T. cantori); and the absence of a pair of white ventro-lateral stripes along the sides of the body in T. davidi sp. nov. (vs. present in T. cantori) [Whitaker and Captain 2008].
|Etymology||Named after Patrick David, eminent French reptile taxonomist, for his immense contribution to the systematics of Asian pit vipers and, in particular, to the Nicobar snake fauna.|