Abstract:To understand the current status of chiropteran species diversity in the northwest and southwest regions of China, we conducted a field survey in Qinghai in July 2023. Six bat specimens (3♀ 3♂) were collected via harp nets and mist nets in Xunhua Salar Autonomous County, Haidong City, Qinghai Province, China. Morphological and molecular systematics methods were used for species identification. These bats possess a medium body size, with a forearm length of 51.45 ± 2.18 mm (49.03 ~ 54.29 mm, n = 6). The ear measures 16.96 ± 1.52 mm (15.30 ~ 18.86 mm, n = 6) and does not extend beyond the rostrum tip when folded forward. The tragus is short at 7.48 ± 1.07 mm (5.83 ~ 8.65 mm, n = 6), approximately half the ear length. The skull snout is low and upturned with a low and flat forehead. The greatest skull length measures 17.99 ± 0.13 mm (17.85 ~ 18.17 mm, n = 4), with a braincase height of 7.00 ± 0.27 mm (6.60 ~ 7.22 mm, n = 4). The upper gear row length is 6.84 ± 0.25 mm (6.52 ~ 7.12 mm, n = 4) (Appendix 1). The second upper and lower premolars are extremely small and located in the dentition. The dorsal pelage exhibits brown coloration with blackish-gray tips, while the ventral pelage displays black hairs tipped with grayish-white (Fig 1). These characteristics demonstrate congruence with the external morphology and cranial features of Myotis pequinius. The Bayesian phylogenetic analysis results showed that the Qinghai specimens clustered with the M. pequinius from other regions. The genetic distance between the Qinghai specimens and the M. pequinius distributed in Shaanxi was the closest (Appendix 2).The species was identified as M. pequinius, a new record in Qinghai Province. The research results enriched the species diversity and distribution data of Chiroptera in China, and provided basic information for the phylogeographic research of M. pequinius.