A new family of mammals recorded in Xizang: Sicistidae

In August 2023, one specimen was collected from Chentang Town, Dingjie County, Xizang Autonomous Region. Dorsally, the hair of this specimen is dark yellowish-brown, interspersed with short black hair, with no black stripes seen along the back. The ventral hair is light yellowish-brown, and markedly distinct from the dorsal color. The tail is longer than head-and-body length and exhibits distinct dorsal and ventral color. The ears are short and round, covered with thick, short, chocolate-colored hair. Its anterior palatine foramina are shorter, extending backwards only to the level of the middle of the premolar, and the posterior edge of the palate is closely aligned to the third upper posterior molar. The second upper molar teeth are of the same length and width, and have an overall square shape. These characteristics are consistent with those of the type specimen of Sicista concolor leathemi, as are the 4 body measurements and 10 skull measurements. Thus, the morphological traits indicate that the Xizang specimen is Sicista concolor leathemi. A phylogenetic analysis based on Cyt b sequences confirmed that the Xizang individual clusters together with other specimens of S. c. leathemi with strong support (PP = 0.95). The average K2P distance between the specimen and other species of Sicista was 22.9%. We recovered significant differences between Sicista concolor leathemi and the other two subspecies of Sicista concolor. Based on these results, we recognize Sicista leathemi as an independent species. This represents the first record of the family Sicistidae in Xizang.