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

## TL;DR

A new skink species, Scincella heishuiensis, was discovered in the Hengduan Mountains of China, increasing the known diversity of the genus.

## Contribution

The formal description of a new Scincella species based on molecular and morphological data from the Hengduan Mountains.

## Key findings

- Scincella heishuiensis is a new species distinguished by unique morphological and genetic traits.
- The new species forms a sister group with S. wangyuezhaoi and is genetically distinct by 5.45% in 16S rRNA.
- The discovery increases the number of Scincella species in China to 17.

## Abstract

The skink genus Scincella, a member of the family Scincidae, is characterized by a wide distribution and conservative morphology. This study integrates molecular and morphological data to conduct phylogenetic analyses and comparative morphology of Scincella population in the Hengduan Mountains. Our findings include the discovery of a new species and the clarification of its phylogenetic relationships within the genus. Significant morphological differences were observed between specimens collected from Heishui County and other known Scincella species. When combined with phylogenetic analysis results, these specimens were identified as a new species, formally described as Scincella heishuiensis sp. nov. Phylogenetic reconstruction reveals that Scincella heishuiensis sp. nov. forms a sister group with S. wangyuezhaoi while exhibiting distinct morphological differentiation from all other Scincella species. This study not only enriches the diversity of the genus Scincella but also provides new insights into its phylogeny history and evolutionary patterns. The results indicate that the diversity of Scincella in the Hengduan Mountains is underestimated and requires further research and exploration.

The genus Scincella 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 Scincella 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 Scincella heishuiensis sp. nov. Phylogenetically, the new species is most closely related to S. wangyuezhaoi, 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 S. wangyuezhaoi 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 Scincella in China to 17 species.