Hidden diversity of rock geckos within the Cnemaspis siamensis species group (Gekkonidae, Squamata): genetic and morphological data from southern Thailand reveal two new insular species and verify the phylogenetic affinities of C. chanardi and C. kamolnorranathi

Abstract

Two new insular rock geckos in the genus Cnemaspis are described from Ko Samui in Surat Thani Province and Ko Similan in Phang-nga Province, southern Thailand, based on a combination of morphological and mitochondrial NADH dehydrogenase subunit 2 (ND2) data. Both new species represent divergent lineages within the Cnemaspis siamensis species group. Cnemaspis samui sp. nov. is distinguished from other species in the group by having eight or nine supralabial and infralabial scales; 5–8 pore-bearing precloacal scales in males, pores rounded; 25–27 paravertebral tubercles, arranged randomly; 22–25 subdigital lamellae under 4th toe; enlarged median subcaudal scale row present; gular region, abdomen, limbs and subcaudal region yellowish only in males, and uncorrected pairwise divergences of 8.86–26.83% from all other species in the C. siamensis species group. Cnemaspis similan sp. nov. is distinguished from other species in the group by having eight or nine supralabial and seven or eight infralabial scales; one pore-bearing precloacal scale in males, pore rounded; 24 or 25 paravertebral tubercles, arranged randomly; 23 or 24 subdigital lamellae under 4th toe; no enlarged median subcaudal scale row; pale yellow reticulum on head, neck, flanks, belly and limbs in male only, and uncorrected pairwise divergences of 9.34–27.11% from all other species in the C. siamensis species group. Cnemaspis samui sp. nov. is found along granitic rocky stream outcrops of Hin Lad Waterfall, Ko Samui, Gulf of Thailand, while Cnemaspis similan sp. nov. occurs in granitic rocky outcrops near Ao Nguang Chang Bay, Ko Similan, Andaman Sea. The phylogenetic analyses confirmed that C. chanardi and C. kamolnorranathi are also nested within the C. siamensis species group, as previously hypothesized from morphology and color pattern characters.