First description of the male and hemipenial morphology of Opisthotropis haihaensis Ziegler et al., 2019 (Serpentes, Natricidae), with updated diagnosis and distribution

BACKGROUND: The Haiha Mountain Stream Keelback, Opisthotropis haihaensis Ziegler, Pham, Nguyen, Nguyen, Wang, Wang, Stuart & Le, 2019, was originally described based on a single female specimen from northern Vietnam. To date, only two female specimens have been reported, rendering O. haihaensis one of the least studied members of its genus. NEW INFORMATION: During recent herpetological surveys in Guangxi Zhuang Autonomous Region, southern China, one male and one female specimen of Opisthotropis were collected from Qinzhou City. Phylogenetic analyses and detailed morphological comparisons identified these individuals as O. haihaensis. Based on these new specimens, we provide the first description of the male of this species, including hemipenial morphology, along with revised diagnostic features and new data on its natural history and distribution.