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Dromornithidae (the dromornithids) were a clade of large, flightless Australian birds of the Oligocene through Pleistocene epochs. All are now extinct. They were long classified in Struthioniformes, but are now usually classified as Anseriformes.〔Murray, P. F. & Megirian, D. (1998)〕〔Murray, P. F. & Vickers-Rich, P. (2004)〕 Dromornithids were part of the Australian megafauna. One species, ''Dromornis stirtoni'', was tall. The collective term Australian megafauna is used to describe a number of comparatively large species of animals that lived in Australia until 50,000 to 20,000 years ago. The causes for the disappearance of these animals are under dispute, though hunting by humans has been identified as a potential instigator.〔Miller, G. H. ''et al.'' (1999)〕〔Roberts, R. G. ''et al.'' (2001)〕 It is also not clear to what degree dromornithids were carnivores. The massive, crushing beaks of some species suggest that at least some members of the family were a combination of carnivorous predators and scavengers (much like today's hyenas) or omnivores. Other features, such as the "hoof-like" feet, stomach structure, and eye structure that resulted in a wide field of vision but likely also created a centre blind spot of about forty degrees (which would hinder hunting significantly) suggest a more herbivorous, migratory lifestyle. The scientific name Dromornithidae derives from Greek δρομαίος, ''dromaios'' ("swift-running") and ὀρνις, ''ornis'' ("bird"). Additionally, the family has been called thunder birds, giant emus, giant runners, demon ducks and mihirungs.〔''Mihirung paringmal'' is an Aboriginal word from the Tjapwuring people of western Victoria, that means 'giant bird'.〕 ==Classification== What the nearest relatives of this group are is a controversial issue. For many years it was thought that dromornithids were related to ratites, such as emus, cassowaries and ostriches. It is now believed that the similarities between these groups are the result of similar responses to the loss of flight. The latest idea on dromornithid relationships, based on details of the skull, is that they evolved early in the lineage that includes waterfowl. 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「Dromornithidae」の詳細全文を読む スポンサード リンク
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