Re-Evaluation of Sinocastor (Rodentia: Castoridae) with Implications on the Origin of Modern Beavers

摘要: The extant beaver, Castor, has played an important role shaping landscapes and ecosystems in Eurasia North America, yet the origins early evolution of this lineage remain poorly understood. Here we use a geometric morphometric approach to help re-evaluate phylogenetic affinities fossil skull from Late Miocene China. This specimen was originally considered Sinocastor, later transferred Castor. aim study determine whether form is member or if it represents outside compared 38 specimens modern Castor (both C. canadensis fiber) as well fiber (Pleistocene), californicus (Pliocene) castorids Steneofiber eseri (early Miocene). results show that falls morphospace Sinocastor possesses a: 1) narrower post-orbital constriction, 2) anteroposteriorly shortened basioccipital depression, 3) incisive foramen, 4) more posteriorly located palatine 5) longer rostrum, 6) braincase. Also shows much shallower basiocciptal depression than what seen living prominently rooted molars. We conclude valid genus. Given prevalence apparently primitive traits, might be near relative gave rise implying possible Asiatic origin for