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The Euarchonta are a grandorder of mammals containing four orders: the Dermoptera or colugos, the Scandentia or treeshrews, the extinct Plesiadapiformes, and the Primates. The term "Euarchonta" (meaning "true ancestors") first appeared in the general scientific literature in 1999, when molecular evidence suggested that the morphology-based Archonta should be trimmed down to exclude Chiroptera. Major DNA sequence analyses of predominantly nuclear sequences (Murphy et al., 2001) support the Euarchonta hypothesis, while a major study investigating mitochondrial sequences supports a different tree topology (Arnason et al., 2002). A study investigating retrotransposon presence/absence data has claimed strong support for Euarchonta (Kriegs et al., 2007). Some interpretations of the molecular data link Primates and Dermoptera in a clade (mirorder) known as Primatomorpha, which is the sister of Scandentia. In some, the Dermoptera are a member of the primates rather than a sister group. Other interpretations link the Dermoptera and Scandentia together in a group called Sundatheria as the sister group of the primates. Euarchonta and Glires together form the Euarchontoglires, one of the four Eutherian clades. }} }} }} The current hypothesis, based on molecular clock evidence, suggests that the Euarchonta arose in the Cretaceous period, about 88 million years ago, and diverged 86.2 million years ago into the groups of tree shrews and Primatomorpha. The latter diverged prior to 79.6 million years into the orders of Primates and Dermoptera.〔Jan E. Janecka, Webb Miller, Thomas H. Pringle, Frank Wiens, Annette Zitzmann, Kristofer M. Helgen, Mark S. Springer und William J. Murphy: ''Molecular and Genomic Data Identify the Closest Living Relative of Primates.'' In: ''Science.'' 318. 2007, 792-794 ((PDF ) 384 KB)〕 However, the earliest fossil species that can be confidently ascribed to Euarchonta (''Purgatorius coracis'') dates to the early Paleocene, 65 million years ago.〔O'Leary, M. A., Bloch, J. I., Flynn, J. J., Gaudin, T. J., Giallombardo, A., Giannini, N. P., ... & Cirranello, A. L. (2013). The placental mammal ancestor and the post–K-Pg radiation of placentals. ''Science'', 339(6120): 662-667.〕 == References == * Murphy W. J., E. Eizirik, W. E. Johnson, Y. P. Zhang, O. A. Ryder, S. J. O'Brien, 2001a. Molecular phylogenetics and the origins of placental mammals ''Nature'' 409:614-618. () * Ulfur Arnason, et al. Mammalian mitogenomic relationships and the root of the eutherian tree. ''Proceedings of the National Academy of Science'' 99: 8151-8156. () * Jan Ole Kriegs, Gennady Churakov, Jerzy Jurka, Jürgen Brosius, and Jürgen Schmitz (2007) Evolutionary history of 7SL RNA-derived SINEs in Supraprimates. Trends in Genetics 23 (4): 158-161 (PDF version ()) 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「Euarchonta」の詳細全文を読む スポンサード リンク
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