A New Species of the Genus <i>Scincella</i> Mittleman, 1950 (Squamata: Scincidae) from the Hengduan Mountains, Sichuan Province, Western China

The genus <i>Scincella</i> Mittleman, 1950 of the family Scincidae currently includes 50 species. However, due to challenges in sample collection, the taxonomy and phylogeny of this genus remain poorly resolved. This study conducted a taxonomic study of the genus <i>Scincella</i> based on three mitochondrial gene fragments (12S, 16S, COI) combined with morphological comparisons. The results indicated the specimens collected in Heishui County, Sichuan Province, China, represented a previously undescribed species. This new taxon is formally described as <i>Scincella heishuiensis</i> <b>sp. nov</b>. Phylogenetically, the new species is most closely related to <i>S. wangyuezhaoi</i>, which is another species recently described in Wenchuan County, Aba Prefecture, Sichuan Province. As a new species, the uncorrected genetic distance between this new species and its closest relative within the genus, as calculated based on 16S rRNA, is 5.45%. The new species can be distinguished from other closely related species by the following morphological characters: (1) 4 dorsal scale rows between dorsolateral stripes; (2) 5–7 superciliary; (3) 28 midbody scale-rows; (4) 24–25 gulars; (5) during the breeding season, the ventral scales and preanal exhibit a reddish-brown color; and (6) a black lateral stripe extends from behind the eye to the posterior third of the tail near the cloaca. In the phylogenetic analysis, the new species and <i>S. wangyuezhaoi</i> form an independent lineage, distinctly separate from all other taxa included in the study. The new species has currently been recorded and discovered in Heishui County in Sichuan Province, China. This description thus increases the number of members in the genus <i>Scincella</i> in China to 17 species.