Simple SummaryThe taxonomic status ofMyotis aurascenshas been debated. Based on morphological and molecular data, our study showed thatM. aurascenswas closely related toM. ikonnikovi,M. alcathoe, andM. mystacinusand was not a synonym forM. davidii. Therefore, the integrated analysis demonstrated thatM. aurascensshould be considered a distinct species rather than a synonym ofM. davidii. This study clarified the taxonomic status ofM. aurascens, which should help enrich biodiversity and improve the species determination of bats in China.AbstractBat groups have a high degree of species diversity, and the taxonomic status and phylogenetic relationships among bat species have always been research hotspots. Due to the fact that morphological characteristics do not always reflect the evolutionary relationships among species, mitochondrial DNA has been widely used in the study of species relationships due to its maternal inheritance pattern.Myotis aurascenshas been suggested as a possible synonym forM. davidii. However, the status of this classification has been controversial. In this study, the morphological and molecular characteristics of aM. aurascenscaptured from Inner Mongolia, China, were analyzed to determine its taxonomic status. In terms of morphological features, the body weight was 6.33 g, the head and body length were 45.10 mm, the forearm length was 35.87 mm, and the tragus length was 7.51 mm. These values all fell within the species signature data range. Nucleotide skew analysis of the protein-coding genes (PCGs) suggested that only five PCGs (ND1,ND2,COX2,ATP8, andND4) showed AT-skew value within the mitogenome ofM. aurascens. Except forND6, the GC-skew values of the other PCGs were negative, reflecting the preference for C and T bases compared to G and A bases. Molecular phylogenetic analyses based on mitochondrial PCGs indicated thatM. aurascenswas a distinct species fromM. davidiiand phylogenetically closer toM. ikonnikovi,M. alcathoe, andM. mystacinus. Genetic distance analysis also showed thatM. aurascensandM. davidiiwere distantly related. Therefore, the integrated analysis demonstrated thatM. aurascensshould be considered a distinct species rather than a synonym ofM. davidii. Our study could provide a reference for enriching species diversity and research on conservation in China.