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''Palaelodus'' is an extinct genus of birds distantly related to flamingos. They were slender birds with long, thin legs and a long neck. Little is known about the shape of their skull or beak. Some paleontologists think ''Palaelodus'' was able to swim under water, chasing prey, but the morphology of their feet seems not very well adapted for diving. Rather, it is more likely that they were adapted to browsing for food while swimming or standing in shallow water. The family, Palaelodidae, is the sister taxon of modern flamingos, and the order Phoenicopteriformes, to which both belong, probably evolved from a grebe-like ancestor. It is easy to see how a bird like ''Palaelodus'' represents an intermediate form between a diving, fish-eating grebe and a wading, invertebrate-filtering flamingo. This does not mean that the palaelodids are the ancestors of the flamingos. Rather, they were a sister group that remained in the ecological niche of their common ancestor. ==Species== The number of species in the genus is disputed. The species ''P. ambiguus'' was found in Middle Oligocene to Middle Miocene (c. 29-12 mya) deposits of Western and Central Europe, being rare in Oligocene and much more common in Miocene strata (Hugueney ''et al.'', 2003). The Romanian fossil ''Grus miocaenicus'' is sometimes considered a synonym of this species. Other, somewhat doubtful species described from the Late Oligocene to Early Miocene (c. 28-23 mya) of French inland sites are ''P. gracilipes'' and ''P. crassipes'' which are most common in the Late Oligocene and later are replaced by ''P. ambiguus'' (Hugueney ''et al.'', 2003). From Late Oligocene to Middle Miocene (c. 28-12 mya) sites in Australia, two species, ''P. pledgei'' and ''P. wilsoni'' have been described. The latter was also claimed from Middle Pleistocene deposits (roughly half a million years ago) in Australia; given the large temporal gap, it might not belong to the genus. On the other hand, the supposed crane ''Pliogrus germanicus'' is most likely a palaelodid. Sometimes ''Megapaloelodus goliath'' is included in ''Palaelodus''. ==References== * Hugueney, Marguerite; Berthet, Didier; Bodergat, Anne-Marie; Escuillié, François; Mourer-Chauviré, Cécile & Wattinne, Aurélia (2003): La limite Oligocène-Miocène en Limagne-changements fauniques chez les mammifères, oiseaux et ostracodes des différents niveaux de Billy-Créchy (Allier, France). ''Geobios'' 36: 719-731 (in French with English abstract ) (HTML abstract) * * * 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「Palaelodus」の詳細全文を読む スポンサード リンク
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