First Asian Record of Pantolestes (Mammalia, Pantolesta, Pantolestidae) From the Upper Eocene of Xinjiang, China

The intercontinental distribution of closely related mammals provides critical insights into paleogeography and paleoenvironments. During the late Eocene, mammalian faunas between North America and Asia show evidence of exchange, but the instances of the same genera on two continents were rare. This limits our understanding of their dispersal patterns. Here, we describe new pantolestid fossils from Asia. Detailed morphological comparisons identify them as a new species, Pantolestes densus sp. nov., closely related to North American species P. natans. This is the first record of Pantolestes in Asia. We also reidentify a late Eocene North American specimen previously identified as cf. P. natans as cf. P. densus. This finding suggests the existence of a corridor connecting North America and Asia during the late Eocene that facilitated the dispersal of Pantolestes. Since Pantolestes is thought to have been semi-aquatic or aquatic based on cranial and postcranial evidence, P. densus likely adapted to a similar lifestyle. https://zoobank.org/urn:lsid:zoobank.org:pub:A909A2D6-FDF3-4637-9DBB-F99784D221DC