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''Eremopezus'' is a prehistoric bird genus. It is known only from the fossil remains of a single species, the huge and presumably flightless ''Eremopezus eocaenus''. This was found in Upper Eocene Jebel Qatrani Formation deposits around the Qasr el Sagha escarpment, north of the Birket Qarun lake near Faiyum in Egypt. The rocks its fossils occur in were deposited in the Priabonian, with the oldest dating back to about 36 million years ago (Ma) and the youngest not less than about 33 Ma.〔Rasmussen ''et al.'' (1987, 2001)〕 It is not precisely known from which strata the first few remains of this bird were collected. They were formerly considered of Early Oligocene age—some 33-30 Ma—but this is now assumed incorrect, as only the upper and not the entire Jebel Qatrani Formation is of Oligocene age. It is also possible that they are from the slightly older Qasr el Sagha Formation, but as both this and the Oligocene parts of the Jebel Qatrani Formation were laid down in an ecosystem markedly different from that of the Eocene Jebel Qatrani Formation, it is now assumed that all material of ''E. eocaenus'' is from the lowest rocks of the Jebel Qatrani Formation.〔Brodkorb (1963) pp.205-206, Rasmussen ''et al.'' (1987, 2001)〕 ==Material, taxonomy and systematics== It was originally described from a distal left tibiotarsus piece (specimen BMNH A843); a toe phalanx bone found soon thereafter was tentatively assigned to this bird. ''Eremopezus'' was initially believed a ratite and loosely allied with the elephant birds of Madagascar. Thus, when a piece of tarsometatarsus shaft was found some time later north of the ruins of Dimeh (Dimê; itself a bit north of the Birket Qarun) this was described as ''Stromeria fajumensis''; though it had a size to match the holotype tibiotarsus it was thought to resemble an elephant bird even more. The shaft (specimen BSPG 1914 I 53) has a prominent plantar (backside) ridge also found in ''Mullerornis betsilei'', and this was used to ally the fossil bone with this rather small and gracile elephant bird. The ''Eremopezus'' specimen on the other hand has deep ligamental pits on the lateral and medial sides of the distal condyles, which are not found in the elephant birds proper. These pits together with a crisply defined ridge held a sling of ligament, which in turn—in place of the bony supratendinal bridge found in some other birds—kept the ankle tendons from dislocating. The tarsometatarsus is also more similar to that of an unspecific ratite, such as an emu, ostrich or rhea, rather than to the apomorphic one of the elephant birds.〔 Almost 100 years after the discovery of the holotype, more ''Eremopezus'' fossils were unearthed from the famous quarry L-41 at Tel Akgrab near . These are also all leg and foot bones, namely specimens DPC 20919 (a distal right tibiotarsus and its entire tarsometatarsus), DPC 5555 (the lower half of a left tarsometatarsus) and DPC 18309 (the distal end of a left tarsometatarsus).〔Rasmussen ''et al.'' (2001)〕 Some fossil eggshells from the Maghreb, described as ''Psammornis'' and resembling those of ratite eggs, were assigned to ''Eremopezus'' by various authors. They were at first believed to date form the Paleogene also, but today are generally considered far younger (of late Neogene age, probably less than 5 Ma) and indeed to have been laid by ostriches or close relatives thereof.〔Brodkorb (1963): p.205, Rasmussen ''et al.'' (2001)〕 The scientific name ''Eremopezus eocaenus'' is rather ambiguous in meaning; a possible translation is "walking hermit from the Eocene". ''Eremos'' (ἐρῆμος) is an Ancient Greek term signifying a lonely or solitary place or person: a hermit, a desert or a wasteland. Yet while Faiyum is located at the edge of the Libyan Desert, it is a well-vegetated location even today; some 35-30 Ma it was a lush region and teemed with life. On the other hand, is it not at all likely that such a large and quite likely predatory bird like ''E. eocaenus'' was in any way gregarious or occurred at high population densities. It might therefore be described as a "hermit" with some justification, but certainly not as a "desert-dweller". ''pezus'' is Latinized Greek from ''pezós'' (πεζός), "someone who walks". ''eocaenus'' refers to the bird's age; as noted, the initial 1904 assessment of C. W. Andrews was indeed correct. ''Stromeria fajumensis'' was named in honor of the paleontologist Ernst Stromer von Reichenbach, and the bone's place of discovery.〔Woodhouse (1910), Rasmussen ''et al.'' (1987), Gagnon (1997)〕 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「Eremopezus」の詳細全文を読む スポンサード リンク
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