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Chimaerasuchidae ("Chimera crocodiles") is a family of mesoeucrocodylians. It was erected as a clade in 2004 by Carvalho ''et al'' and included ''Chimaerasuchus'' from the Early Cretaceous of China and Simosuchus from the Late Cretaceous of Madagascar. The validity of the clade has been questioned in later studies that found the two genera to be more distantly related. ==Phylogeny== In the phylogenetic analysis of Carvalho ''et al'', the family contained ''Chimaerasuchus'' and ''Simosuchus'', two genera of small (~1 metre long), possibly herbivorous crocodyliforms from the Cretaceous. Both had short-snouted heads with multicusped teeth. Carvalho ''et al'' placed Chimaerasuchidae within a new clade of mesoeucrocodylians called Gondwanasuchia. It was the sister taxon of Notosuchimorpha, another newly erected clade that contained notosuchias, sebecosuchians, and peirosaurids. Below is a modified cladogram from Carvalho ''et al'' (2004): }} }} }} }} }} }} 3 Terriasuchia, 4 Peirosaurimorpha, 5 Peirosauriformes The Carvalho ''et al.'' (2004) paper phylogeny did not include neosuchians in the analysis. Neosuchians and notosuchians are the two major clades of mesoeucrocodylians. When neosuchians are included in analyses with ''Simosuchus'' and ''Chimaerasuchus'', the two genera do not appear as sister taxa (Pol 2003; Candeiro & Martinelli 2006). In fact ''Chimaerasuchus'' has been found to be the sister taxon of ''Sphagesaurus''. ''Sphagesaurus'' is often assigned its own family, Sphagesauridae. If ''Chimaerasuchus'' belongs to Shagesauridae, Chimaerasuchidae would be a junior synonym of Sphagesauridae. This is because Sphagesauridae was named before Chimaerasuchidae, and under ICZN rules, the oldest name has priority. In a recent contribution, Marinho & Carvalho (2007) did a revision of Sphagesauridae and noticed that ''Chimaerasuchus'' does not have any of the synapomorphies of this family that was originally erected by Kuhn (1968). In this new paper, the authors propose an emended diagnosis for the Sphagesauridae, pointing new synapomorphies for this taxon and propose that the Chimaerasuchidae would be a valid family in spite of the poor phylogenetic analysis of Carvalho ''et al.'' (2004) paper. 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「Chimaerasuchidae」の詳細全文を読む スポンサード リンク
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