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| Paraxenodermus borneensis (Boulenger, 1899) (ZRC 2.5731), from Crocker Range, Sabah, in the north-western Borneo. in Deepak, Lalronunga, Lalhmingliani, et al. 2021. DOI: 10.3897/vz.71.e75967 Photograph by Indraneil Das. |
Abstract
Xenodermidae is a generally poorly known lineage of caenophidian snakes found in South, East and Southeast Asia. We report molecular phylogenetic analyses for a multilocus data set comprising all five currently recognised genera and including new mitochondrial and nuclear gene sequence data for the recently described Stoliczkia vanhnuailianai. Our phylogenetic results provide very strong support for the non-monophyly of Stoliczkia, as presently constituted, with S. borneensis being more closely related to Xenodermus than to the Northeast Indian S. vanhnuailianai. Based on phylogenetic relationships and morphological distinctiveness, we transfer Stoliczkia borneensis to a new monotypic genus endemic to Borneo, Paraxenodermus gen. nov. We also present new morphological data for P. borneensis.
Key words: Borneo, endemic, morphology, Paraxenodermus gen. nov., phylogeny, taxonomy
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| Line drawings of Stoliczkia khasiensis (A, B), Stoliczkia vanhnuailianai (C, D) and Paraxenodermus borneensis (E, F) based on ZSIK 14945, BNHS 3656 and BMNH 1946.1.15.58 respectively. Genus characteristics are highlighted in different colours: 1) some supralabials in contact with eye in Stoliczkia, separated by circumorbital scales in Paraxenodermus; 2) fewer supra- and infralabials in Stoliczkia than in Paraxenodermus; 3) single prefrontal in Stoliczkia versus 2–3 in Paraxenodermus, 4) fewer scales between parietal and supralabials immediately behind eye in Stoliczkia than in Paraxenodermus, and 5) small row of scales between frontal and prefrontals absent in Stoliczkia, present in Paraxenodermus. Note small scales behind the temporals are indicative rather than precisely accurate. Pale grey coloured areas are bare skin exposed between scales. Illustrations by V. Deepak and Surya Narayanan. Scale bars = 10 mm. |
Systematics
Stoliczkia — (Jerdon, 1870)
Content— S. khasiensis (Fig. 3A–B) and S. vanhnuailianai (Fig. 3C–D)
Diagnosis: This genus can be diagnosed based on the combination of the following features: (1) maxillary teeth small and subequal, (2) head very distinct from (much wider than) ‘neck’, with large shields on dorsal aspect, (3) posterior one-third of the head and posterior temporal region covered with small scales like those of the anterior end of the body, (4) 3 small scales between parietal and supralabial shields immediately behind eye (5) 8–9 supralabials, (6) nostril in a large concave nasal, (7) body slender and somewhat laterally compressed, (8) ventrals large, and (9) dark dorsum and pale venter meet along a regular straight line ventrolaterally and subcaudals partially or completely darker than venter.
Distribution: This genus is restricted to Northeast India (Fig. 1). Stoliczkia khasiensis is thus far known only from Khasi hills, Meghalaya state, India and the recently described Stoliczkia vanhnuailianai is known only from Mizoram state, India.
Etymology: The genus is named after the Moravian-born Ferdinand Stoliczka (1838–1874). A geologist-natural historian, he was appointed as a palaeontologist with the Geological Survey of India in 1863. Stoliczka collected vertebrates and molluscs from northern India, Andaman and Nicobar Islands, Myanmar and the Malay Peninsula. He served as the official Naturalist with the Second Mission to Yarkand, in central Asia. A biography and a list of published works and reports by Stoliczka can be found in Kolmaš (1982).
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| Paraxenodermus borneensis in life (ZRC 2.5731), from Crocker Range, Sabah, in the north-western Borneo. Sequences for this specimen was published in Vidal and Hedges (2002) and used in this study. Photograph by Indraneil Das. |
Paraxenodermus, gen. nov.
Type species: Paraxenodermus borneensis (Boulenger, 1899).
Type locality: Mount Kinabalu, North Borneo (4,200 ft / 1,280 m); the holotype is deposited in the Natural History Museum, London as BMNH 1946.1.15.58; collected by Richard Hanitsch in March, 1899.
Diagnosis: This genus can be diagnosed based on the combination of the following features: (1) maxillary teeth small and subequal, (2) head very distinct from (much wider than) ‘neck’, with large shields on dorsal aspect, (3) posterior one-third of the head and posterior temporal region covered with small scales like those of the anterior of the body, (4) numerous small scales between parietal and supralabial shields immediately behind eye, (5) a row of 4–6 small scales between the frontal and prefrontal shields, (6) 10–11 supralabials, (7) nostril in a large concave nasal, (8) body slender and somewhat laterally compressed, (9) ventrals large, and (10) dorsum with numerous dorsolateral and middorsal pale blotches, venter pale with brown patches and subcaudals dark grey.
Etymology: The generic name Paraxenodermus is composed of the modern Latin generic name Xenodermus and the Latin adjective par (paris), meaning, among other possibilities, “similar to”.
Paraxenodermus borneensis (Boulenger, 1899).
V. Deepak, Samuel Lalronunga, Esther Lalhmingliani, Abhijit Das, Surya Narayanan, Indraneil Das and David J. Gower. 2021. Phylogenetic Relationships of Xenodermid Snakes (Squamata: Serpentes: Xenodermidae), with the Description of A New Genus. Vertebrate Zoology. 71: 747-763. DOI: 10.3897/vz.71.e75967
