Taxonomic reassessment of two subspecies of Chinese skink in Taiwan based on morphological and molecular investigations (Squamata, Scincidae)

The Chinese skink, Plestiodon chinensis (Gray, 1838), is widely distributed across continental China, Taiwan, the Korean Peninsula, and offshore islets, and consists of several subspecies. Here morphological and molecular methods have been used to reassess the taxonomic status and distributions of P. c. formosensis (Van Denburgh, 1912) and P. c. leucostictus (Hikida, 1988), which are endemic to Taiwan and Green Island (an islet off the east coast of Taiwan), respectively. It can be confirmed that the eastern Taiwanese populations of P. c. formosensis exhibit similar juvenile color patterning and genetic composition to the islet subspecies P. c. leucostictus, and are distinct from consubspecific populations in western Taiwan. Therefore, the eastern Taiwanese populations are assigned to P. c. leucostictus, and this subspecies is recognized as a distinct species, Plestiodon leucostictus (Hikida, 1988), based on their unique juvenile coloration and highly divergent DNA sequences. Our results also revealed that P. c. formosensis in western Taiwan is close to nominotypical subspecies from the continent, suggesting the necessity of a comprehensive taxonomic analysis in the future.