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''Otavia antiqua'' is an early sponge-like fossil found in Namibia in the Etosha National Park. It is claimed to be the oldest animal fossil, being found in rock aged between 760 and 550 million years ago. The genus was named after the Otavi group in which the fossils were found. The oldest fossils are prior to the Cryogenian glaciations, but the latest found were from the Nama group rocks which are from the Ediacaran period. The shape of the fossils is irregular but rounded. The size varies from a third of a millimetre to . They are hollow inside, and have many small holes connecting the interior to the outside. The material of the outer wall is predominantly calcium phosphate.〔 These affinity of these fossils, along with other paleontological evidence for precambrian sponges, is disputed. ==Further reading== * *(【引用サイトリンク】url=http://www.physorg.com/news/2012-02-namibia-sponge-fossils-world-animals.html ) 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「Otavia」の詳細全文を読む スポンサード リンク
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