Lectotype designation of Plestiodon elegans (Reptilia: Squamata: Scincidae) and the Description of a New Species of the Plestiodon elegans Complex from Northwestern Yunnan Province, China

The Elegant Skink, Plestiodon elegans, was described based on syntype specimens from southeastern China, and it is recorded as widely distributed, expanding across multiple zoogeographic regions. Although previously identified populations have been shown to represent misidentifications of other congeners, many questionable populations remain unexamined, including the ones from Yunnan Province. To clarify the taxonomic status of the Yunnan populations, we designate a lectotype of Plestiodon elegans and revise the diagnosis of the species based on its type series. Mitochondrial genealogies recover the population of “P. elegans” from northwest Yunnan as paraphyletic to the true P. elegans, displaying over 11% of divergences based on the COI gene. Morphologically, the population from northwest Yunnan can be diagnosed from P. elegans and closely aligned congeners by the absence of enlarged scales posterolateral of cloaca, having a different number of postmental, paravertebral, and midbody scale rows, and a distinct body coloration in adults. Therefore, we describe the northwest Yunnan population as a new species. We discussed the validity of two other members of the P. elegans complex, namely P. liui and P. popei, synonymized P. popei with P. elegans, and updated the diagnostic key to all members of the genus Plestiodon in China.