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Gallornis
''Gallornis'' is a genus of prehistoric birds from the Cretaceous. The single known species ''Gallornis straeleni'' lived near today's Auxerre in Yonne ''département'' (France); it has been dated very tentatively to the Berriasian-Hauterivian stages, that is about 140–130 million years ago. The known fossil material consists of a worn partial femur and a fragment of the humerus.〔Hope, Sylvia (2002): The Mesozoic radiation of Neornithes. ''In:'' Chiappe, Luis M. & Witmer, Lawrence M. (eds.): Mesozoic Birds: Above the Heads of Dinosaurs: 339-388. ISBN 0-520-20094-2〕
This is a highly significant taxon for theories about the evolution of birds. Unfortunately, it is not known from much or well-preserved material. It has been proposed that the remains show features only known from the Neornithes – the group of birds that exists today. Thus, the ''Gallornis'' fossils suggest that as early as about 130 million years ago or more the ancestors of all living birds might already have been an evolutionary lineage distinct from the closely related Hesperornithes and Ichthyornithes (essentially modern birds retaining some more ancient features like teeth) and the more distantly related Enantiornithes (a group of more primitive toothed birds which were the most successful avians in the Mesozoic).
== Ecology ==
During the time of ''Gallornis'', its range was located around 30°N, north of the Tropic of Cancer aridity belt. However, the Cretaceous was a hot and humid age in general, so the habitat might have more resembled West Africa around the Gulf of Guinea. Higher sealevels had large parts of Europe submerged for much of the time, and Southeast Europe and Asia Minor had not even attached to that continent yet (see also Haţeg Island, Haţeg Basin). The Alpide orogeny (the uplift of the Eurasian latitudinal mountain belt) had not even gotten underway.
''Gallornis'' was a contemporary of many (non-avian) dinosaurs living around the (Second) Tethys Sea. In the archipelago that was then Europe, huge sauropods appear to have been the dominant herbivores.〔E.g. the camarasaurid ''Aragosaurus ischiaticus'', the diplodocoid ''Histriasaurus boscarollii'', the huge plesiomorphic Turiasauria, or the very peculiar and smallish (for a sauropod - some 15 meters or more) ''Xenoposeidon proneneukos''〕 Apart from some early birds, pterosaurs roamed the skies of the European microcontinents, (more abundant and diverse than the few bird species), while semi-aquatic crocodylomorphs (e.g. ''Goniopholis'', ''Pholidosaurus'', ''Vectisuchus'') and marine thalattosuchians were common. Stegosaurs were apparently rare (e.g. ''Regnosaurus northamptoni''). Theropods like ''Concavenator'' and ''Baryonyx'' may have existed alongside it as well.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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