Abstract:During a field investigation in Xintian Town, Pengshui Miao, and Tujia Autonomous County, Chongqing in July 2022, two Odorrana specimens were found (Fig. 1). The purpose of this study is to identify the species using morphological and phylogenetic methods, as well as to ascertain its distribution in Chongqing.A comparative analysis of the morphological characteristics of the species discovered from Chongqing and O. wuchuanensis from Guizhou and Hubei was conducted. For phylogenetic analyses, mitochondrial 16S rRNA fragments were amplified, and the 16S rRNA gene information of 11 Odorrana species from China and abroad was obtained from the GenBank database (Table 1). Corresponding sequences of one Pseudorana weiningensis and one Nidirana daunchina were also downloaded and used as outgroups. The maximum likelihood phylogenetic tree was constructed in IQ-TREE, the Bayesian tree construction was carried out in MrBayes 3.2.1, and the best-fit model was selected according to the Bayesian inference criteria (BIC) computed with JModelTest 0.1.1. Morphological characteristics appear to differ little between those specimens of Chongqing, Guizhou, and Hubei (Fig. 2). The snout vent length of the male species discovered in Pengshui was 81.3 mm, which was longer than the maximum snout vent length of the type specimen and O. wuchuanensis from Jianshi County, Hubei Province. The female of the species had a snout vent length of 87.1 mm, which was within the range of the type specimen’s body snout vent length but smaller than the female O. wuchuanensis from the Jianshi County (Table 2). Genetic analysis based on the mitochondrial 16S rRNA gene revealed that the specimens found in Pengshui County of Chongqing clustered with O. wuchuanensis from Wuchuan County of Guizhou Province with a high support (Fig. 3). The genetic distance between O. wuchuanensis in Wuchuan County, Guizhou Province, and the specimens found in Pengshui County is 0 (Table 3). According to a thorough comparison with morphological analysis and phylogenetic analysis, the specimens discovered in Pengshui were identified as O. wuchuanensis, which is a new record of amphibian distribution in Chongqing.
