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Dental remains of a medium sized beaver from the early Late Miocene Hammerschmiede locality (MN 7/8) in the Northern Alpine Foreland Basin (Southern Germany, Bavaria) are described and assigned to Steneofiber depereti. The numerous material (160 teeth) was collected in the two fossiliferous layers HAM 5 and HAM 4 and comprises beaver individuals of a large range of age classes, from juvenile to old. The dental remains metrically and morphologically overlap the stratigraphic older Steneofiber spp. and the younger Chalicomys spp. This supports the hypothesis of the European anagenetic evolutionary lineage Steneofiber depereti-Chalicomys jaegeri. The morphological characters to differentiate Steneofiber depereti and Chalicomys jaegeri are discussed and redefined. The performed age-frequency distribution (Mortality profile) indicates a natural ecological mortality and confirms that at least the fluvial channel of the HAM 4 deposits was the actual optimal beaver habitat and continuously populated by larger family groups of beavers. Furthermore, there are indications that the Hammerschmiede beaver had a similar parental investment as today's beavers, where young adults migrate to poorer habitats in the second year, in search of their own territory. The shallower channel of HAM 5 possibly represents such a "second choice" habitat. [ABSTRACT FROM AUTHOR]

Two genera of Miocene beavers (Castoridae), Hystricops and Priusaulax are referred to a new tribe Hystricopini of the subfamily of giant beavers, Castoroidinae based on cranial and dental morphologies. Previously undescribed and more complete specimens of Hystricops demonstrate that it is referable to the Castoroidinae rather than the Castorinae. Along with Priusaulax, it is believed to represent a group of basal castoroidines, distinct from later Castoroidinae by the retention of the primitive morphology of the contact of the lacrimal bone with the jugal on the cranium, as well as more primitive dental morphologies (lower crown-height and simple occlusal pattern of cheek teeth). A partial cranium and several isolated teeth from the Hemingfordian of Colorado, originally referred to Anchitheriomys?, are referred here to a new species, Priusaulax wilsoni sp. nov. Monosaulax senrudi from the Barstovian of Montana is also referred to Priusaulax. Hystricops is limited to the type species H. venustus from the Clarendonian and Barstovian North American Land Mammal Age (NALMA), and H. browni from the Hemphillian NALMA. [ABSTRACT FROM AUTHOR]