page_title: Eremopezus
section_title: Size and flightlessness
hierarchical_section_title: Eremopezus / Description / Size and flightlessness
caption_attribution_description: Afrikaans: Gompou, Ardeotis kori Burchell, Etosha Nasionale Park, Namibië العربية: حباري كوري (Ardeotis kori) في برتشل بحديقة إستوتشتا الوطنية في زامبيا. Català: Ardeotis kori Burchell, Etosha, Namíbia Čeština: Ardeotis kori Burchell, Etosha Národní park, Namibie Dansk: Ardeotis kori Burchell, Etosha Nationalpark, Namibia Deutsch: Riesentrappe Ardeotis kori Burchell, Etosha Nationalpark, Namibia English: Kori Bustard Ardeotis kori Burchell, Etosha National park, Namibia Esperanto: Koria otido , Ardeotis kori Burchell, Etosha Nacia parko, Namibio Español: Ardeotis kori Burchell, Etosha Parque nacional, Namibia Eesti: Ardeotis kori Burchell, Etosha Rahvuspark, Namibia Suomi: Kuningastrappi , Ardeotis kori Burchell, Etosha Kansallispuisto, Namibia Français&#160;: Outarde kori , Ardeotis kori Burchell, Etosha Parc national, Namibie Galego: Ardeotis kori Burchell, Etosha, Namibia Magyar: Óriás túzok Ardeotis kori Burchell, Etosha Nemzeti park, Namíbia Italiano: Ardeotis kori Burchell, Etosha Parchi nazionali, Namibia Lëtzebuergesch: Ardeotis kori Burchell, Etosha, Namibien Lietuvių: Ardeotis kori Burchell, Etošos duburys, Namibija Nederlands: Koritrap , Ardeotis kori Burchell, Etosha Nationaal park, Namibië Norsk bokmål: Ardeotis kori Burchell, Etosha Nasjonalpark, Namibia Polski: Drop olbrzymi, Ardeotis kori Burchell, Etosha Park narodowy, Namibia Português: Abetarda-gigante , Ardeotis kori Burchell, Etosha Parque nacional, Namíbia Русский: Африканская дрофа-кори , Ardeotis kori Burchell, Этоша (национальный парк), Намибия Slovenčina: Ardeotis kori Burchell, Etosha Národný park, Namíbia Slovenščina: Ardeotis kori Burchell, Etosha Narodni park, Namibija Svenska: Koritrapp, Ardeotis kori Burchell, Etosha Nationalpark, Namibia 中文: 灰颈鹭鸨 Ardeotis kori Burchell, 埃托沙鹽湖, 纳米比亚
context_page_description: Eremopezus is a prehistoric bird genus, possibly a palaeognath. 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 and the youngest not less than about 33 Ma.
  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.
context_section_description: E. eocaenus was somewhat ponderous, at about the body size of Mullerornis betsilei. As this was one of the heavy-boned elephant birds, Eremopezus was probably lighter than it, especially if it retained the air-filled bones of flying ancestors. From the ground to the pelvis, it stood probably as high as a large rhea or small emu—slightly less than one meter in all probability –, though the robust bones of the prehistoric bird appear to have supported a larger bulk than those of the fleet-footed ratites.  Altogether, even if it was not particularly long-necked Eremopezus must have stood about as high as an average adult human. It weighed probably less than 50 kg—slightly more than a large emu—and more than 10 kg—slightly more than the largest living storks (which reach over 150 cm in height) and the shoebill.
  The general limit for weight in flying birds is at about 25 kg, the exceptional Argentavis magnificens with its size and weight of a good-sized adult human notwithstanding as it evolved under unusual ecological conditions. Large males of the kori bustard (Ardeotis kori) and great bustard (Otis tarda) are perfectly capable of flight, while weighing in excess of 20 kg. A wing loading of c. 25 kg/m² is the known limit for bird flight under normal circumstances; thus, a case could be made for Eremopezus to have been capable of flight. Paleontologists do not consider this likely however, due to the stoutness of the bones, which in such a degree is only known from birds that were certainly flightless. The secretarybird's tarsometatarsus, for example, is only some 20% shorter but more than 60% slimmer than that of E. eocaenus. Thus, its wings and arm bones were probably reduced, a process known to have taken as little as 10,000 years in some island rails.
caption: Adult kori bustard (Ardeotis kori). Perhaps, E. eocaenus was only as heavy as this bird
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