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Imagotaria
''Imagotaria'' is an extinct monotypic genus of walrus with the sole species ''Imagotaria downsi''. Fossils of ''Imagotaria'' are known from the early late Miocene of California (c. 10-12 million years ago). ==Description== The long pinniped more closely resembled in its overall shape a sea lion rather than a walrus. Unlike the extant walrus (''Odobenus rosmarus''), ''Imagotaria'' did not possess elongate, ever-growing tusks, but instead bore enlarged canines (with respect to other pinnipeds). ''Imagotaria'' is an example of a primitive walrus that does not grossly appear similar to a modern walrus. However, the walrus family (the Odobenidae) is a more inclusive group, that includes walruses without tusks (e.g. ''Imagotaria''), walruses with upper and lower tusks (the subfamily Dusignathinae), and walruses with upper tusks like the extant walrus (subfamily Odobeninae, tribe Odobenini). It is possible to classify these pinnipeds as walruses because they share many other skull features (besides tusks) as well as many skeletal features, all of which indicate common ancestry.
抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Imagotaria」の詳細全文を読む
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