Wednesday, February 12, 2020

[Herpetology • 2020] Asthenodipsas borneensis • A Taxonomic Revision of Asthenodipsas malaccana Peters, 1864 (Squamata: Pareidae) with A Description of A New Species from Borneo

Asthenodipsas borneensis 
Quah, Grismer, Lim, Anuar & Chan, 2020

DOI: 10.11646/zootaxa.4729.1.1 
photo: Anton Sorokin

A reappraisal of the taxonomic status of the Dark-necked Slug Snake (Asthenodipsas malaccana Peters, 1864) across its range revealed that populations from Borneo are not conspecific with true A. malaccana from the Thai-Malay Peninsula and Sumatra, and is therefore described herein as new. Asthenodipsas borneensis sp. nov. can be distinguished from A. malaccana and other congeners by the absence of a preocular and suboculars, seven or eight supralabials with 3rd and 4th in contact with orbit, 4–7 infralabials with 2nd or 3rd pair in contact, two pairs of posterior inframaxillaries, 15/15/15 rows of dorsal scales, presence of sharp vertebral keel, divided subcaudals, maximum recorded SVL=441 mm, 166–179 ventrals, 35–48 subcaudals, head white to greyish brown and dorsum beige to orange-brown with a conspicuous dark-brown or black patch on the neck followed by multiple, narrow, vertical, dark bands along the rest of the body and tail. This discovery adds to a growing number of new slug snake species recently described from Southeast Asia and highlights the underestimated diversity in this family, especially in Borneo. Taxonomic revisions of the reptiles and amphibians of Borneo are still needed before the true diversity of the island and the relationships of the various taxa can be fully understood.

Keywords: Reptilia, Pareas, Sundaland, slug snake, systematics, discovery, reptile, conservation, endemic biodiversity, Malaysia, Indonesia

FIGURE 3. Asthenodipsas borneensis sp. nov. from Borneo.
A: Specimen from Kuching, Sarawak (LSUDPC 10988). B: Specimen from Sayap, Mount Kinabalu, Sabah (LSUDPC 10982). C -F (LSUDPC 10983-10986): Adults from Poring, Sabah. G & H (LSUDPC 10987 & 10978): Juvenile from Poring, Sabah.
(Photographs by Chien C. Lee [A & B], Zhou Hang [C & D], 
Anton Sorokin [E & F] & Jaroslav Karhánek [G & H]).

Asthenodipsas borneensis sp. nov. Adult from Poring, Sabah 
photo: Anton Sorokin 

Asthenodipsas borneensis sp. nov. (LSUDPC 10988) from Kuching, Sarawak. 

Photo: Chien C. Lee. 

Asthenodipsas borneensis sp. nov.
Bornean Dark-necked Slug Snake

Etymology. The specific epithet borneensis is in reference to its restriction to the island of Borneo. The suffix ensis is a Latin derivation meaning “from” or “inhabiting.” It renders the specific epithet an adjective that must be in grammatical accord with the gender of Asthenodipsas that is feminine (Frank Tillack in litt. 2019).

Asthenodipsas malaccana Peters, 1864:
Adult female (LSUHC 12740) from Gunung Besar Hantu, Negeri Sembilan, Peninsular Malaysia.

Photo: Chan Kin Onn

Evan S. H. Quah, L. Lee Grismer, Kelvin K. P. Lim, Shahrul Anuar and Kin Onn Chan. 2020. A Taxonomic Revision of Asthenodipsas malaccana Peters, 1864 (Squamata: Pareidae) with A Description of A New Species from Borneo. Zootaxa. 4729(1); 1–24. DOI:  10.11646/zootaxa.4729.1.1