Sphenomorphus tamchucensis sp. nov. (Squamata, Scincidae), a new skink from Vietnam.

A new skink species, Sphenomorphus tamchucensis sp. nov., is described from Ninh Binh Province, northern Vietnam, based on morphological and molecular evidence. The new species can be distinguished from other Sphenomorphus species by a combination of the following characteristics: size medium (maximal SVL 41.5 mm); primary temporals two; external ear opening without lobules; loreals two; supralabials seven; infralabials six; nuchals absent; midbody scales in 28 rows; dorsal scales smooth, in six rows across the back; paravertebral scales 58-63, not widened; ventral scales in 55-61 rows; 8-10 smooth lamellae beneath finger IV and 13-15 beneath toe IV; toes not reaching to fingers when limbs adpressed along body; dorsal surface of body and tail bronze brown with many tiny dark dots and a discontinuous dark vertebral stripe, from middle of neck to tail base; a black stripe, in two scales wide, running from nostril to eye and extending from posterior margin of eye along upper part of flank to middle of tail. In phylogenetic analyses, the new species is recovered as an independent lineage with no clear sister taxon and at least 17.85% genetic divergence from other congeners based on a fragment of the mitochondrial COI gene.