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Proneotherium
''Proneotherium'' is an extinct genus of pinniped that lived approximately 20.43 to 15.97 mya during the Early Miocene in what is now Oregon, U.S. It belonged to the family Odobenidae, the only extant species of which is the walrus. Discovery Four specimens of ''Proneotherium'' were discovered in the Astoria Formation of Lincoln County, Oregon, U.S. These specimens included cranial and postcranial remains and are all believed to be adult male animals. Description ''Proneotherium'' were more similar in appearance to modern fur seals and sea lions than walruses. They lacked the long tusks of walruses, and were more slender and smaller than their modern relatives. Autapomorphies of ''Proneotherium'' fossils include a continuous, horizontal crest connecting the mastoid and paroccipital processes of the skull. The teeth are also less secodont in function and appearance than more basal species. This likely represents the slow shift from a piscivorous diet to the mollusk-based d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odobenidae
Odobenidae is a family of pinnipeds. The only living species is the walrus (''Odobenus rosmarus''). In the past, however, the group was much more diverse, and includes more than a dozen fossil genera. Taxonomy All genera, except ''Odobenus'', are extinct. *†''Archaeodobenus'' *†''Prototaria'' *†''Proneotherium'' *†'' Nanodobenus'' *†''Neotherium'' *†''Imagotaria'' *†'' Kamtschatarctos'' *†''Pelagiarctos'' *†''Pontolis'' *†'' Pseudotaria'' *†''Titanotaria'' *Clade Neodobenia **†'' Gomphotaria'' **Subfamily Dusignathinae ***†'' Dusignathus'' **Subfamily Odobeninae ***†''Aivukus'' ***†'' Ontocetus'' ***†'' Pliopedia'' ***†'' Protodobenus'' ***†''Valenictus'' ***''Odobenus The walrus (''Odobenus rosmarus'') is a large flippered marine mammal with a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. The walrus is the only living species in the fami ...'' In re-analyzing ''Pela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |