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''Volaticotherium antiquum'' was an actively mobile ancient gliding insectivorous mammal that lived in what would become Asia during the Jurassic period, around 164 mya. It is the only member of the genus ''Volaticotherium''. It had a gliding membrane similar to a modern-day flying squirrel. The teeth of ''Volaticotherium'' were highly specialized for eating insects, and its limbs were adapted to living in trees. The gliding membrane (patagium) was insulated by a thick covering of fur, and was supported by the limbs as well as the tail. The discovery of ''Volaticotherium'' provided the earliest-known record of a gliding mammal (70 million years older than the next oldest example), and provided further evidence of mammalian diversity during the Mesozoic Era. The closely related ''Argentoconodon'' shows similar post-cranial adaptations for aerial locomotion also seen in ''Volaticotherium'', and the also closely related ''Ichthyoconodon'' occurs in marine deposits, having probably gotten there by flight. The phylogenetic analysis conducted by the authors of the description of ''Volaticotherium antiquum'' recovered it as the sister taxon of the clade that contained, among other taxa, eutriconodonts, multituberculates, spalacotheriid and tinodontid "symmetrodontans", dryolestids, metatherians (including marsupials) and eutherians (including placental mammals). As the analysis did not place ''Volaticotherium'' within any of the previously known main groups of Mesozoic mammals, the authors of its description erected a separate family Volaticotheriidae and order Volaticotheria for it.〔 However, Zhe-Xi Luo (2007) mentioned that ''Volaticotherium'' might actually be a eutriconodont. This was eventually confirmed by the phylogenetic analyses conducted by Leandro C. Gaetano and Guillermo W. Rougier (2011, 2012); these analyses recovered ''Volaticotherium antiquum'' as a eutriconodont that belonged to the family Triconodontidae and subfamily Alticonodontinae, and was particularly closely related to the genera ''Argentoconodon'' and ''Ichthyoconodon''. The only known fossil of ''Volaticotherium'' was recovered from the Daohugou Beds of Ningcheng County, Inner Mongolia, China. The age of the Daohugou Beds is currently uncertain and the subject of debate, but most studies suggest an age of around 164 plus or minus 4 million years ago. The description was published in an issue of the journal ''Nature''. ==References== * 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「Volaticotherium」の詳細全文を読む スポンサード リンク
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