Nessia gansi: a Second Three-toed Snake-Skink (Reptilia: Squamata: Scincidae) from Sri Lanka with the Designation of a Neotype for Nessia burtonii Gray

Abstract

Abstract A new species of Nessia is described from Sri Lanka. Nessia gansi sp. n. is distinguished from its sister species (N. burtonii) based on the morphological and meristic data. The new species differs from all other congeners except N. burtonii Gray, by a combination of following characters: presence of four limbs; all limbs bearing three digits; interparietal broader than frontal. It distinguishes from N. burtonii by having five (vs. six) supraciliaries; one (vs. two) pretemporal/s; two (vs. one) primary temporal/s; three (vs. four) infralabials; 93-105 (vs. 110-124) paravertebral scale rows; 103-114 (vs. 117-121) ventral scales; two (vs. three) subdigital lamellae under each digit of manus; mental as wide as postmental (vs. mental wider than postmental); and nostrils visible when viewed ventrally (vs. not visible). Two closely related species show a discrete distribution in Sri Lanka: N. gansi sp. n. is recorded from Kanneliya, Rumaswala, Kottawa, Panagula, Ambalangoda and Imaduwa in the first and second peneplains (~100 m), whereas N. burtonii records (here corrected) are reported from Alagalla, Ambagamuwa, Gampola, Hiniduma and Kandy within the third peneplain (from ~500 m). The identity of N. burtonii is stabilized through the designation of a neotype, and here it is re-described.