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''Concornis'' is a genus of enantiornithine birds which existed during the early Cretaceous period, in the late Barremian age or about 125 million years ago, and its remains are known from the Calizas de La Huérguina Formation at Las Hoyas, Cuenca province, Spain. The single known species ''Concornis lacustris''〔Etymology: "Lacustrine bird from Cuenca province". ''Concornis'', from Latin ''Conca'' (the Roman name of the Cuenca region) + Ancient Greek ''ornis'' (όρνις) "bird". ''lacustris'', Latin for "lacustrine", "of the lake".〕 was described from remains of one individual skeleton which is not quite complete but bears feather impressions.〔Sanz & Buscalioni (1992)〕 This was a smallish bird, measuring maybe 13 cm (12.5 in) without tail (). Its weight was probably some 75g or more, possibly over 100 g.〔 Nothing is known about its skull, but it was almost certainly still toothed and somewhat snout-like as in its relatives. It was probably an accomplished flyer for its time, though perhaps not as nimble and somewhat lacking in stamina compared to modern birds. It is not known whether it had an alula and it must have possessed a long, narrow pygostyle not known to be associated with Neornithes-like rectrices.〔Clarke ''et al.'' (2006)〕 The legs were fairly long and neither dedicated to perching on branches nor to running on the ground; it had a large hallux as is generally absent in terrestrial birds.〔 ==Systematics== Initially it was believed to be more primitive than Enantiornithes;〔 these were at that time little-known and, as the primitive ''Iberomesornis'' was not yet considered to belong there either, contained only very advanced taxa. With more and more enantiornithine material becoming known, the placement of ''C. lacustris'' in this group was eventually verified. In fact, despite its early age, ''C. lacustris'' seems by no means primitive among the Enantiornithes. It is sometimes considered a member of the Enantiornithiformes and related to ''Enantiornis''; others reject this placement. A cladistic analysis including many enantiornithine taxa places it in the "Cathayornithiformes", grouping with ''Sinornis'' (or ''Cathayornis'') and, surprisingly, ''Neuquenornis volans'' which was hitherto believed to belong to a different lineage of Euenantiornithes.〔Mortimer (2004)〕 Whichever of the two competing hypotheses may be correct, they provide evidence that the Euenantiornithes were accomplished flyers capable of crossing oceans, as in either case close relatives of ''Concornis inhabited South America. A relationship with ''Sinornis/Cathayornis'' is suggested mainly by a peculiarly autapomorphic sternum. There is a keel that is small compared to that of modern birds, "Y"-shaped, and the end of the sternum bears deep notches〔 like in the Chinese bird. 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「Concornis」の詳細全文を読む スポンサード リンク
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