The taxonomic status of Asthenodipsas vertebralis in Borneo has been plagued with uncertainty over the last eighty years. An examination of museum collections resulted in the discovery of a voucher specimen of A. vertebralis from Sarawak, East Malaysia that confirms the presence of the species in Borneo and a previously unrecognised species, Asthenodipsas ingeri sp. nov. from Mount Kinabalu, Sabah. Asthenodipsas ingeri sp. nov. can be differentiated from its congeners by the combination of an absence of preoculars and suboculars, 1st and 3rd pair of infralabials in contact, two pairs of posterior inframaxillaries, supralabials 3-5 (sometimes 3 4) in contact with orbit, 15/15/15 rows of dorsal scales, presence of sharp vertebral keel, and divided subcaudals. This study highlights the importance of careful re-examination of museum collections that could potentially harbour new species hiding in plain sight. These discoveries also add to the growing number of reptile and amphibian species being described from Borneo that shows no signs of abating but are already potentially threatened by the continued deforestation and developments on the island.
A review of the taxonomic status of the Smooth Slug Snake (Asthenodipsas laevis) in Borneo resulted in the discovery of two previously unrecognised species from the highlands of Sabah, East Malaysia. Asthenodipsas jamilinaisi sp. nov. and A. stuebingi sp. nov. are presumed to be closely related to A. laevis based on similarities in pholidosis and patterning but can be separated from A. laevis by their dorsal scale rows of 15/15/15 vs 15/15/13 and the presence of a sharp vertebral keel. Asthenodipsas jamilinaisi sp. nov. can be further differentiated from A. stuebingi sp. nov. by the greatly enlarged size of the vertebral scales, higher number of ventrals in males (173-175 vs 165), higher number of subcaudals (53 vs 35-47) and colour pattern (dark overall with indistinct bands vs lighter head and body with clear, distinct bands and a dark neck patch). The discovery highlights the need for more careful examination of much of the herpetofauna of Borneo that still remains underestimated and understudied. There is an urgent need for continued surveys into its diversity and the collection of genetic material for integrated taxonomic revisions.
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.
There is an urgent need for reliable data on the impacts of deforestation on tropical biodiversity. The city-state of Singapore has one of the most detailed biodiversity records in the tropics, dating back to the turn of the 19th century. In 1819, Singapore was almost entirely covered in primary forest, but this has since been largely cleared. We compiled more than 200 y of records for 10 major taxonomic groups in Singapore (>50,000 individual records; >3,000 species), and we estimated extinction rates using recently developed and novel statistical models that account for "dark extinctions," i.e., extinctions of undiscovered species. The estimated overall extinction rate was 37% (95% CI [31 to 42%]). Extrapolating our Singapore observations to a future business-as-usual deforestation scenario for Southeast Asia suggests that 18% (95% CI [16 to 22%]) of species will be lost regionally by 2100. Our extinction estimates for Singapore and Southeast Asia are a factor of two lower than previous estimates that also attempted to account for dark extinctions. However, we caution that particular groups such as large mammals, forest-dependent birds, orchids, and butterflies are disproportionately vulnerable.