Resolving taxonomic uncertainty in Chinese Myotis through molecular and morphometric integration in the Eastern Region of China (Mammalia: Chiroptera: Vespertilionidae)

Abstract The taxonomy of genus Myotis (Chiroptera: Vespertilionidae) has long posed considerable challenges, with numerous species in China remaining poorly defined. To address long-standing taxonomic ambiguities in Chinese Myotis , this study integrates over 15 years of fieldwork and conducts a comprehensive assessment of 197 specimens collected primarily in eastern China, which represent approximately 70% of the country’s known species. Molecular species delimitation, phylogenetic reconstruction, and multivariate analyses of morphological data were jointly employed to reassess species diagnostic traits. Phylogenetic and molecular delimitation supported the validity of 30 Myotis species in China, and resolved several long-debated complexes, including M. davidii , M. siligorensis , and M. frater . Principal component and hierarchical clustering analyses revealed mixed and overlapping patterns among species, particularly within small to medium size taxa. These results highlighted the limitations of traditional morphometric traits for distinguishing closely related Myotis . Initial classification accuracy using morphological traits alone was modest. However, when categorical phenotypic data was added into the dataset, model performance improved markedly: Random forest accuracy increased from 77.9% to 90.5%, and the decision tree model successfully discriminated 16 taxonomic units. These suggested that categorical phenotypic data can substantially enhance identification within morphologically conservative groups. Based on integrative evidence, we established an updated identification key. In addition, high-resolution 3D digital models of craniodental structures were generated to facilitate open access for future research. This study provided a foundation for subsequent phylogeny, ecology, and conservation biology studies on this taxonomically difficult genus.