Rediscovery and revalidation of Sinomicrurus wongii Fan, 1931 (Squamata, Elapidae), from South China and northern Vietnam following nearly a century of obscurity

At present, both Calliophis wongii Fan, 1931, and Sinomicrurus houi Wang, Peng & Huang, 2018, are regarded as junior synonyms of Sinomicrurus kelloggi. In this study, we revalidate the species status of C. wongii based on morphological and molecular evidence and confirm S. houi as a junior synonym of C. wongii. Two road-killed specimens of Sinomicrurus were collected from Napo in 2024, which morphologically best match the original description of C. wongii.

Analyses of the mitochondrial COI and Cyt b genes reveal that these specimens form a well-supported clade with S. houi (uncorrected p - distance: 1.3 % for COI, <2 % for Cyt b) but are significantly divergent from S. kelloggi (7.7 % for COI, 5.5–6.1 % for Cyt b), values that exceed the commonly accepted interspecific threshold within the genus. Sinomicrurus wongii comb. nov. is mainly distinguished from S. kelloggi by possessing seven infralabials and narrow black dorsal bands.

Based on available data, we also clarify the distribution of C. wongii, which occurs in Guangxi, Yunnan, and Hainan, China, as well as in Hai Duong and Cao Bang, Vietnam.