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.