Family : PAREIDAE
Species : Asthenodipsas lasgalensis
Maximum Size : 73 cm

First described in 2013, the Mirkwood Forest Slug Snake Asthenodipsas lasgalensis is a close relative of the Mountain Slug Snake Asthenodipsas vertebralis, with which it was formerly confused.

The most obvious difference between the two species is only apparent in adults: while both species are brownish in colour, adult Asthenodipsas lasgalensis lose the dark banding which is present in juveniles, and which is particularly evident on the lower flanks of Asthenodipsas vertebralis throughout life.

In addition the venter and labial (lip) scales of the former are white, and in the latter are yellow. Presence or absence of a vertebral stripe also varies between the species, although this feature is less obvious in the field.

For both species, the length of the tail comprises around 20% of total length.

Asthenodipsas lasgalensis is known from four montane areas of Peninsular Malaysia, namely Maxwell Hill (= Bukit Larut), Fraser's Hill, Cameron Highlands and Genting Highlands, where it is sympatric (i.e. sharing the same habitat) as Asthenodipsas vertebralis.  However, the two species may frequent different vertical niches within the same habitat, although this is unclear: examples of both species have been found on low vegetation near the ground.

At present, Asthenodipsas lasgalensis is known only from montane areas of Peninsular Malaysia above 800 metres elevation, but is seems likely that its range may extend into montane forest habitats of southern Thailand.

Figs 1 to 3 : Two adult examples from Maxwell Hill (= Bukit Larut), Perak, Peninsular Malaysia at an elevation of around 1200 metres.  Images thanks to Serin Subaraj.


References :

Ariel I. Loredo, Perry L. Wood, Jr., Evan S. H. Quah, Shahrul Anuar, Lee F. Greer, Norhayati Ahmad & L. Lee Grismer  (2013). Cryptic speciation within Asthenodipsas vertebralis (Boulenger, 1900) (Squamata: Pareatidae), the description of a new species from Peninsular Malaysia, and the resurrection of A. tropidonotus (Lidth de Jude, 1923) from Sumatra: an integrative taxonomic analysis. Zootaxa 3664 (4): 505-524.