Family : PAREIDAE
Species : Asthenodipsas laevis
Maximum Size : 60 cm

The Smooth Slug Snake occurs in lowland and montane primary and secondary forest, often near stream courses. In Peninsular Malaysia it is recorded up to at least 760 metres elevation, based on the details accompanying specimen ZRC.2.2745 held at the Lee Kong Chian Natural History Museum, Singapore. In Borneo, it occurs at higher elevations up to 1523 metres, based on details recorded with specimen ZRC.2.2742.

This is a nocturnal snake, and largely terrestrial or fossorial, but it may climb into low vegetation in search of prey.

As with other slug snakes, this species is a specialist feeder which has evolved to feed on slugs and snails. Its dentition is unequal, with a greater number of teeth on one lower jaw than on the other, which allows it to extract snails from their shell. A diagnostic feature of all members of the family Pareidae is the presence of chin scales that are assymetric, and thus there is no median furrow (see Fig 4).

Its body is moderately slender, and somewhat laterally compressed. Its short head is distinct from the neck, and the snout is blunt, short and rounded. The dorsum is medium brown, with irregular, dark brown bands that may extend to the venter. The bars are separated by 3 to 5 plain scales.

The ventrum is pale, sometimes light brown or yellowish, and sometimes blotched with brown markings. Its dorsal scales are smooth. The eyes are moderate in size, with a red or brown iris. The vertebral scale row is enlarged, and these scales may be pale orange-brown or yellowish.

The Smooth Slug Snake is rare in the Malay Peninsula, though it has been found in widely separated  localities in southern Thailand, Peninsular Malaysia and Singapore. Its range extends to the islands of Sumatra, Java and Borneo. In Sabah, northeast Borneo, it is quite common in true forest. Record(s) from Laos are likely to be in error.

Figs 1 to 3 : A typical specimen from Sarawak, Borneo.  Photos thanks to Noel Thomas.

Fig 4 : Underside of the head of specimen ZRC 2.7079, a roadkill from Singapore, showing asymmetrical chin scales, and absence of median furrow.


References :

Baker, N., Thomas, N. & Lim, K. K. P. (2014). Second record of the smooth slug snake in Singapore. Singapore Biodiversity Records 2014: 337 - 338. National University of Singapore. [pdf] 

Inger R. F., Lian T.F., 1996. The Natural History of Amphibians and Reptiles in Sabah. Natural History Publications (Borneo) Sdn. Bhd.

Tweedie, M., 1957. The Snakes of Malaya. Raffles Museum, Singapore.