Sunday, May 17, 2020

[Herpetology • 2020] Rhinophis melanoleucus • A New Species of Rhinophis Hemprich, 1820 (Serpentes: Uropeltidae) from the Wayanad Region of peninsular India

Rhinophis melanoleucus 
Cyriac, Narayanan, Sampaio, Umesh & Gowe, 2020

Photograph by Surya Narayanan.

A new species of the shieldtail snake genus Rhinophis is described based on a type series of seven recently collected specimens from the Wayanad region of the Western Ghats of peninsular India. Rhinophis melanoleucus sp. nov. is diagnosed based on a combination of 15 dorsal scale rows at (or just behind) midbody, more than 215 ventral scales and a long rostral. The new species also has a distinctive (mostly black and white) colouration. A new key to the identification of Indian species of Rhinophis is provided.

Keywords: Serpentes, identification key, shieldtail, snakes, taxonomy, Western Ghats

 Holotype (BNHS 3534: total preserved length 461 mm) of Rhinophis melanoleucus sp. nov. in life.
Photograph by Surya Narayanan.
 DOI: 10.11646/zootaxa.4778.2.5

Rhinophis melanoleucus sp. nov. 

Diagnosis. Rhinophis melanoleucus sp. nov. differs from all other species of Rhinophis except R. sanguineus and R. fergusonianus in having 15 dorsal scale rows at (or just behind) midbody (versus 17 or 19 in other congeners). Rhinophis melanoleucus sp. nov. differs from R. fergusonianus in having > 215 ventrals (known range 218–236) versus 195 in the only known specimen of R. fergusonianus. Rhinophis melanoleucus sp. nov. differs from R. sanguineus in having more ventral scales (218–236 versus 181–214 in specimens examined here – see Discussion for comment on Wall’s 1919 report of ventral counts in R. sanguineus of up to 218), in having dark blotches (versus spots) on the ventral surface, and in having a proportionately longer rostral shield: 40.8–42.9% (n = 7; mean 42.0%) versus 32–39.3% (n = 17; mean 36.9%) of head length (= distance between snout tip and posterior edge of fourth supralabial). Only a single nomen is currently considered a synonym of any Indian Rhinophis species—R. microlepis Beddome, 1863 is a subjective junior synonym of R. sanguineus (e.g. Beddome 1886, Smith 1943, Gans 1966, McDiarmid et al. 1999, Pyron et al. 2016). The holotype of R. microlepis differs from the type series of the new species in having a mottled or speckled rather than blotched venter, in having fewer than 218 ventrals (214), and in having a shorter rostral shield (35.8% of head length versus 41% or more).

Etymology. From the Ancient Greek mélas (black) and leukós (white), in reference to the unusual (for uropeltids) black and white colouration. For nomenclatural purposes, the species name melanoleucus is a noun in the genitive case.

Distribution, habitat, natural history and conservation status. Rhinophis melanoleucus sp. nov. is known only from the vicinity of Lakkidi in the Wayanad District of Kerala state, at approximately 750–850 m elevation in the evergreen hills of the Western Ghats. The habitat in the vicinity of the type locality is shown in Fig. 7. We suspect that the new species has a larger distribution, at least in the Wayanad region, but it is not widespread and/or frequently encountered enough to have been previously collected or reported. The new species is likely to qualify for Data Deficient status under IUCN Red List criteria, at least until new field surveys are undertaken and/or additional specimens from other localities can be found in other collections. 

The holotype was found at 08:00, moving on the surface of a forest track alongside a stream and close to an adjacent tea plantation. Paratypes BNHS 3537 and BNHS 3538 were found at 15:00 and 09:00, respectively, the former dead on a paved road, and the latter on the ground surface in an abandoned coffee plantation. Referred specimen BNHS 3539 was dug from a depth of approximately 0.5 m during excavations for a road extension in mid-elevation wet-evergreen forest (rainfall approximately 5,000 mm per year) with trees including Cinnamomum malabatrum (Burm. f.) J.Presl, Meliosma simplicifolia (Roxb.), Actinodaphne malabarica Balakr. and Elaeocarpus tuberculatus Roxb. in addition to farmed coffee. Paratypes ZSI/WGRC/IR/V/3100 and ZSI/WGRC/IR/V/3101 were found at approximately 07.00 and 18.30 respectively, moving among grass on the side of a tarred road inside the Veterinary and Animal Sciences University campus, Pookode. Paratypes BNHS 3535 and BNHS 3536 were found dead on a tarred road between 07.00 and 08.00. 

In a few days of temporary captivity, BNHS 3538 refused to feed on live earthworms provided. When handled, none of the individuals in the type series attempted to bite. They showed an inclination to burrow in soil and in the hand. At the localities reported here, Rhinophis melanoleucus sp. nov. occurs broadly sympatrically (within a radius of ca. 15 km) with other uropeltids including at least i. sanguineus, Uropeltis cf. nilgherriensis, Teretrurus hewstoni, Melanophidium bilineatum and M. wynaudense.

 Vivek P. Cyriac, Surya Narayanan, Filipa L. Sampaio, Pavukandy Umesh and David J. Gower. 2020. A New Species of Rhinophis Hemprich, 1820 (Serpentes: Uropeltidae) from the Wayanad Region of peninsular India. Zootaxa. 4778(2); 329–342. DOI: 10.11646/zootaxa.4778.2.5