Rhinophis gunasekarai WICKRAMASINGHE, VIDANAPATHIRANA, WICKRAMASINGHE & GOWER, 2020
Can you confirm these amateur observations of Rhinophis gunasekarai?
|Higher Taxa||Uropeltidae, Henophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Common Names||Sinhala: Gunasekarage Thudulla|
Tamil: Gunasekaran nilakael pambu
E: Gunasekara’s sheildtail
|Synonym||Rhinophis gunasekarai WICKRAMASINGHE, VIDANAPATHIRANA, WICKRAMASINGHE & GOWER 2020|
|Distribution||Sri Lanka (Central Province)|
Type locality: Riverstone, Knuckles Massif, Matale District, Central Province, Sri Lanka (07°31’39” N, 80°44’01” E, elevation 1420 m)
|Types||Holotype. NMSL-NH 2020.05.01, male, SVL 258 mm (Figs. 2–4), collected by L.J.M. Wickramasinghe and D.R. Vidanapathirana, on 28 September 2018.|
Paratypes (n=2). Males, NMSL-NH 2020.05.02, SVL 143 mm (Fig. 5A&B); DWC2020.05.01, SVL 154 mm (Fig. 5C&D); collection details same as holotype.
|Diagnosis||Diagnosis. The new species is distinguished from its congeners by the combination of 17 dorsal scale rows at midbody; 177–182 ventrals (Figs. 3B, 5B&D, 6); a small to moderate tail shield covered with small homogenous spines in an approximately radial distribution; 17 yellow, longitudinal lines from slightly more than one head length behind head to level with vent, around body except on ventral scale row; dorsal, lateral and ventral regions of tail entirely blackish, without markings; a single irregular and uneven row of blotches on the ventrolateral surface of the body, visible in ventral view except on the anteriormost region of the body.|
Rhinophis gunasekarai sp. nov. most closely resembles R. phillipsi (Nicholls, 1929), sharing dorsal yellow lines and lateral yellow blotches, and a relatively small tail shield. However, the new species differs from R. phillipsi in having 182 or fewer ventrals (vs 197 or more), lacking yellow lines on the tail (vs present), lacking two larger and notably horizontally projected spines on the tail shield (vs present), having more than 7 yellow lines along the body (vs 7 yellow lines), and in the yellow blotches on the body being visible in ventral aspect (vs not visible).
Among other Sri Lankan congeners, R. gunasekarai sp. nov., differs from R. saffragamus (Kelaart, 1853) by having a small, domed tail shield (vs large and flat), nasal shields separated by rostral (vs nasal shields in contact, behind rostral), and by having dorsal scales in 17 rows (vs 19); from R. dorsimaculatus Deraniyagala, 1941, R. oxy- rhynchus (Schneider, 1801), R. porrectus Wall, 1921, R. punctatus Müller, 1832 and R. zigzag Gower & Maduwage, 2011, by having 200 or fewer ventrals (vs more than 207), and additionally from the former four species by having a moderate-sized tail shield (vs relatively much larger tail shield); from R. lineatus Gower & Maduwage, 2011, by the presence of a row of blotches on the ventrolateral margin of the body (vs absent), absence of an irregular yellow lateral line on the tail (vs present), a relatively shorter distance between rostral and frontal scales (18–20% of rostral length vs 0–14%), and perhaps by having fewer ventrals (177–182 vs 180–195 for known material); from R. blythii Kelaart, 1853, R. erangaviraji Wickramasinghe, Vidanapathirana, Wickramasinghe & Ranwella, 2009, R. melano- gaster (Gray, 1858), and R. tricoloratus Deraniyagala, 1975, in having 170 or more ventrals (vs fewer than 170) a moderate-sized tail shield (vs much larger tail shield), and from R. melanogaster by the absence of two notably large, horizontally projected spines on the tail shield (vs present).
The ventral scale count in R. gunasekarai sp. nov. is similar to or overlapping with that of R. drummondhayi Wall, 1921, R. homolepis (Hemprich, 1820), and R. philippinus (Cuvier, 1829). However, the new species differs from R. drummondhayi in having (vs lacking) longitudinal narrow lines on the dorsum, lacking pale markings on the lateral surface of the tail (vs present), and in having a narrow (vs relatively much wider) tail shield; from R. ho- molepis by the absence (vs presence) of a conspicuous yellow band (1–2 scales wide) around the tail base and by a much less protuberant tail shield; and from R. philippinus by the presence (vs absence) of pale longitudinal lines on the upper surface of the body, and by its much smaller and less protuberant tail shield.
In addition to its colour pattern, Rhinophis gunasekarai sp. nov. differs from all five Indian species of Rhino- phis by having a smaller and less protuberant tail shield. It differs further in having 177–182 ventrals (vs more than 200 in R. goweri Aengals & Ganesh, 2013; 195 in R. fergusonianus Boulenger, 1896; 150 or fewer in R. travanco- ricus Boulenger, 1893; 218–236 in R. melanoleucus Cyriac, Narayan, Sampaio, Umesh & Gower, 2020). Rhinophis gunasekarai sp. nov. also differs from R. sanguineus Beddome, 1863, R. fergusonianus and R. melanoleucus by having 17 dorsal scale rows at or just behind midbody (vs 15).
Coloration in life. Body background dark, blackish rather than the more greyish appearance of the somewhat dehydrated specimen at time of preservation. Seventeen yellow lines from approximately two head lengths behind snout tip to level of vent, distributed evenly around body excluding ventral scale row. Yellow lines narrow, running through centres of body scales (Fig. 2), most prominent dorsally and anteriorly, fading toward posterior and venter (Figs. 6). Single row of conspicuous yellow blotches on ventrolateral surface of body, beginning from two head lengths behind snout tip to level with vent. On right hand side (RHS), anteriormost blotch is on the 6th and 7th dorsal scale rows approximately level with 6th vertebral scale; on the left hand side (LHS), anteriormost blotch is approxi- mately level with the 7th vertebral scale. Blotches irregularly arranged, uneven in size (1–3 scales wide; 2–3 scales tall), anteriormost two blotches more dorsally placed, gradually becoming more lateral in orientation (10th blotch on the 4th dorsal scale row, by mid-body on the 2nd and 3rd or on the 2nd, 3rd and 4th, or on the 3rd and 4th dorsal scale rows). RHS with 35 blotches, 32 on LHS.
Five yellow blotches irregularly placed on anterior of venter midline, from 13th to 36th ventral scale (Fig. 6). Pos- teriormost ventral and centers of divided anal scales forming a conspicuous yellow mark. Dorsal (Fig. 9), lateral (Fig. 10) and ventral (Fig. 7) aspects of tail entirely dark with no pale markings. Tail shield brownish, paler towards apex.
|Etymology||The specific epithet is an eponym latinised as a noun in the genitive singular, honouring Samantha Gunasekara, a Sri Lankan conservationist, for his contributions to the field of biodiversity conservation, especially for his service in establishing a Biodiversity Protection Unit in the Department of Customs, Government of Sri Lanka.|