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Gastornithidae is a family of prehistoric birds. The various species in this group lived from the Paleocene to the Eocene epochs and ranged from Asia and Europe to North America. All known species were very large, flightless ground birds, similar to ostriches but more heavily built and with huge beaks. Once thought to be carnivores, they are now considered to have been primarily herbivorous.〔Witmer, L. & Rose, K. (1991) (Biomechanics of the jaw apparatus of the gigantic Eocene bird ''Diatryma''; implications for diet and mode of life ). ''Paleobiology'' 17(2):95-120.〕〔 Gastornithids are only known from a handful of species. The genus ''Gastornis'' itself contains three European species, as well as the North American species ''G. giganteus'', a well-known prehistoric bird formerly classified as the distinct dodo ''Diatryma''. An Asian species, ''G. xichuanensis'', was originally classified as the distinct genus ''Zhongyuanus''. Apart from these, there are some indeterminate gastornithid species, including ''"Diatryma" cotei'' from the middle-late Eocene of France〔Mlíkovský, J. (2002) ( Birds of the World, Part 1: Europe ). Ninox Press, Prague.〕 Additional, fragmentary fossils that are difficult to classify in any particular genus or species include remains found in Paleocene rocks of Walbeck, Germany, and the specimen YPM PU 13258 from early Eocene rocks of Park County, Wyoming, possibly a juvenile ''G. giganteus''〔Wetmore, A. (1933). (Bird Remains from the Eocene of Wyoming ). ''Condor'', 35(3): 115-118.〕 ==Classification== ''Gastornis'' and its close relatives were long considered to be members of the order Gruiformes. However, the traditional concept of Gruiformes has since been shown to be an unnatural grouping. Beginning in the late 1980s and the first phylogenetic analysis of gastornithid relationships, consensus began to grow that they were close relatives of the lineage that includes waterfowl and screamers, the Anseriformes.〔Mustoe, G.E., Tucker, D.S., & Kemplin, K.L. (2012). "Giant Eocene bird footprints from northwest Washington, USA." ''Palaeontology'', 55(6): 1293-1305.〕 Recognizing the apparent close relationship between gastornithids and waterfowl, some researchers classify gastornithids within the anseriform group itself.〔Agnolin, F. (2007). "''Brontornis burmeisteri'' Moreno & Mercerat, un Anseriformes (Aves) gigante del Mioceno Medio de Patagonia, Argentina." ''Revista del Museo Argentino de Ciencias Naturales'', n.s. 9, 15-25〕 Others restrict the name Anseriformes only to the crown group formed by all modern species, and label the larger group including extinct relatives of anseriformes, like the gastornithids, with the name Anserimorphae.〔Andors, A.V. (1992). "Reappraisal of the Eocene ground bird ''Diatryma'' (Aves: Anserimorphae)." ''Science Series Natural History Museum of Los Angeles County'', 36: 109-125.〕 Gastornithids are therefore sometimes placed in their own order, Gastornithiformes.〔Buffetaut, E. (2002). "Giant ground birds at the Cretaceous-Tertiary boundary: Extinction or survival?" ''Special papers - Geological Society of America'', 303-306.〕 A simplified version of the family tree found by Agnolin ''et al.'' in 2007 is reproduced below. }} }} }} }} 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「Gastornithidae」の詳細全文を読む スポンサード リンク
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