Tuesday, August 22, 2023

[Herpetology • 2023] Sahyadriophis uttaraghati & S. beddomei • Systematic Assessment of Hebius beddomei (Günther, 1864) (Serpentes: Colubridae: Natricinae) with Description of A New Genus and A New Allied Species from the Western Ghats, India


Sahyadriophis uttaraghati
Patel, Thackeray, Campbell & Mirza, 2023

 
Abstract
Hebius beddomei (Günther, 1864) is an endemic natricine colubrid snake species from the biodiverse Western Ghats, India. A recent molecular phylogeny provided evidence for the paraphyly of the genus Hebius, with Hebius beddomei recovered as sister to a clade containing Fowlea and Atretium. Freshly collected specimens and existing museum material allowed us to elucidate the generic status of the species and identify two distinct populations, one of which is described as a new species. A new genus, Sahyadriophis gen. nov., is proposed to accommodate Sahyadriophis beddomei gen. et comb. nov., and Sahyadriophis uttaraghati gen. et sp. nov. is described as a new species from the northern part of the range. The discovery of a new Oligocene divergent lineage, Sahyadriophis gen. nov., highlights the role of the Western Ghats as a source of relic lineages.

Keywords: biodiversity hotspot; integrated taxonomy; molecular phylogeny; natricinae; keelback; Sahyadri

  Images of Sahyadriophis gen. nov. in life,
(a) Sahyadriophis uttaraghati gen. et sp. nov. holotype ♂ NCBS NRC-AA-0024,
(b) juvenile Sahyadriophis beddomei gen. et comb. nov. (uncollected) from Madikeri, (c) adult male Sahyadriophis beddomei gen. et comb. nov. Periyar Tiger Reserve, Kerala;
photos by Harshil Patel (a), Zeeshan A. Mirza (b,c).

Sahyadriophis gen. nov.

Type species. Sahyadriophis uttaraghati gen. et sp. nov.

Species included. Sahyadriophis beddomei gen. et comb. nov. and Sahyadriophis uttaraghati gen. et sp. nov.

Diagnosis. Medium-sized snakes in relation to family members measuring SVL 215–495 mm with 19 dorsal keeled scale rows at mid-body. Head distinct from neck. Nuchal groove and glands absent. Pupil rounded. Nostrils in nasals, a pair or internasals. Paired internasals and prefrontals. Posterior maxillary teeth longest and present after a distinct diastema, 18–26 functional maxillary teeth, 10–15 palatine teeth and 22–25 ptyerogoid teeth. Scales at the sacral region bear dentate keels in males.

Etymology. The generic name is a combination of two words: ‘Sahyadri’, a Sanskrit word for the Western Ghats, and the Greek word ‘ophis’ for snakes. The name is masculine in gender.





Sahyadriophis uttaraghati gen. et sp. nov.
Rhabdophis beddomei Wall, 1923: 605 (in part)
Natrix beddomei Smith, 1943: 306 (in part)
Amphiesma beddomei Whitaler and Captain, 2004: 242 (in part); Wallach et al., 2014: 28 (in part)

Diagnosis. A medium sized snake ranging from SVL 365 to 425mm with 19 keeled dorsal scales at mid-body; nine supralabials; ventrals 145–148 ♂, 151–153 ♀ and subcaudals 78–83 ♂, 74–76 ♀; maxilla with 26 teeth, 14 or 15 pterygoid and 23–24 palatine teeth; pterygoid-palatine oriented nearly parallel to the head and converges to a small degree posteriorly; TaL/TL 0.27–0.30 ♂.

Etymology. The specific epithet is a combination of two Sanskrit words: ‘uttara’ for north and ‘ghati’ meaning dweller of the mountains/Ghats. The combination refers to the northern distribution of the new species.


Sahyadriophis beddomei (Günther, 1864) gen. et comb. nov.
Spilotes vittatus Beddome, 1863: XX
Tropidonotus beddomei Günther, 1864: 269; Boulenger 1890: 344, 1893: 252
Rhabdophis beddomei Wall, 1923: 605 (in part)
Natrix beddomei Smith, 1943: 306 (in part)
Amphiesma beddomei Whitaler and Captain, 2004: 242 (in part); Wallach et al., 2014: 28 (in part), Deepak et al., 2022: 8
Hebius beddomei Guo et al., 2014: 437; Deepak et al., 2022: 7

Diagnosis. A medium-sized natricid ranging from SVL 177 to 495 with 19 keeled dorsal scales at mid-body; eight supralabials (rarely seven or nine); ventrals 140–145 ♂, 143–152 ♀ and subcaudals 71–76 ♂, 62–68 ♀; maxilla with 18 teeth, 12 pterygoid and 20–22 palatine teeth; pterygoid-palatine oriented nearly parallel to the head and does not converge or diverge posteriorly; TaL/TL 0.22–0.26 ♂. Additional morphological characteristics of the species are provided in Table 3.
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 Harshil Patel, Tejas Thackeray, Patrick D. Campbell and Zeeshan A. Mirza. 2023. Systematic Assessment of Hebius beddomei (Günther, 1864) (Serpentes: Colubridae: Natricinae) with Description of A New Genus and A New Allied Species from the Western Ghats, India. Taxonomy. 3(3); 415-434. DOI: 10.3390/taxonomy3030024