18-694: Struthioniformes is an order of birds with only a single extant family, Struthionidae , containing the ostriches . Several other extinct families are known, spanning across the Northern Hemisphere, from the Early Eocene to the early Pliocene , including a variety of flightless forms like the Paleotidae , Geranoididae , Eogruidae and Ergilornithidae , the latter two thought to be closely related to Struthionidae. According to Mayr and Zelenkov (2021), all Struthioniformes are united by
36-490: A separate family, Ergilornithidae , but they are now generally accepted to be a subfamily within Eogruidae. Eogruids are rather similar to Geranoididae , a clade of similar flightless gruiforms from North America and Europe , and both groups have occasionally been classified as sister taxa. Recently geranoidids have been recovered as basal to the rest of Gruoidea, however, while eogruids are sister-taxa to cranes. There
54-508: Is a family of flightless birds , containing the extant ostriches and their extinct relatives. The two extant species of ostrich are the common ostrich and Somali ostrich , both in the genus Struthio , which also contains several species known from Holocene fossils such as the Asian ostrich . The common ostrich is the more widespread of the two living species, and is the largest living bird species . The extinct genus Pachystruthio from
72-650: Is therefore most likely that Struthionidae originated in Asia. The oldest records of Struthionidae, belonging to the genus Struthio , are from the Early Miocene of Africa, around 21 million years old. Struthio dispersed into and became widespread in Eurasia during the late middle- Late Miocene epoch beginning around 12 million years ago. Pachystruthio from the Late Pliocene of Eurasia contains some of
90-655: The Struthioniformes , a group of paleognath birds which first appeared during the Early Eocene , and includes a variety of flightless forms which were present across the Northern Hemisphere (Europe, Asia and North America) during the Eocene epoch. The closest relatives of Struthionidae within the Struthioniformes are the Ergilornithidae , known from the late Eocene to early Pliocene of Asia. It
108-548: The Late Pliocene-Early Pleistocene of Eurasia is one of the largest birds ever. The first species of Struthio appear during the Miocene epoch, though various Paleocene , Eocene , and Oligocene fossils may also belong to the family. Ostriches are classified in the ratite group of birds, all extant species of which are flightless, including the kiwis , emus , and rheas . Traditionally,
126-682: The Northern Hemisphere during the Eocene , including Paleotididae from Europe, and Geranoididae from North America, and Eogruidae and Ergilornithidae in Asia. The discovery of Lumbreornis , belonging to either Paleotididae or Geranoididae, suggests that Struthiorniformes probably also inhabited South America during the Eocene. Ergilornthidae would persist in Asia into the Early Pliocene , while its sister group Struthionidae likely originated from Asia. Ostriches first appeared in Africa during
144-841: The common ostrich by the geographic barrier of the East African Rift . In some areas, the common ostrich's Masai subspecies occurs alongside the Somali ostrich, but they are kept from interbreeding by behavioral and ecological differences. The Arabian ostriches in Asia Minor and Arabia were hunted to extinction by the middle of the 20th century, and in Israel attempts to introduce North African ostriches to fill their ecological role have failed. Escaped common ostriches in Australia have established feral populations. In 2019,
162-401: The early Miocene, around 21 million years ago, before dispersing into Eurasia during the late Miocene, beginning around 12 million years ago. After Mayr, and Zelenkov (2021) Struthionidae Struthionidae ( / ˌ s t r uː θ i ˈ ɒ n ə d iː / ; from Latin strūthiō 'ostrich' and Ancient Greek εἶδος (eîdos) 'appearance, resemblance')
180-572: The end of the last ice age ; images of ostriches have been found there on prehistoric pottery and petroglyphs . Today ostriches are only found natively in the wild in Africa , where they occur in a range of open arid and semi-arid habitats such as savannas and the Sahel , both north and south of the equatorial forest zone. The Somali ostrich occurs in the Horn of Africa , having evolved isolated from
198-416: The following characters: "a very long and narrow tarsometatarsus with short trochleae for the second and fourth toes, a tubercle next to the pons supratendineus on the distal end of the tibiotarsus , as well as a shortening of all non-ungual phalanges of the fourth toe except for the proximal one" All known members of the group are thought to have been flightless. Struthioniformes were widely distributed in
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#1732773119006216-490: The largest bird species ever with some species likely weighing up to 450 kilograms (990 lb). While the relationship of the African fossil species is comparatively straightforward, many Asian species of ostriches have been described from fragmentary remains, and their interrelationships and how they relate to the African ostriches are confusing. In China , ostriches are known to have become extinct only around or even after
234-416: The late Cenozoic of Asia and some species do occur in areas where ostrich fossils have also been found. It has been suggested that the family is paraphyletic , with Ergilornithidae more closely related to modern ostriches than to Eogrus or Sonogrus . Most eogruids are known from rather sparse remains, mostly the tarso-metatarsals and toes. The former are generally slender with a distinct crest along
252-531: The lateral side of the plantar surface. The trochlea for the second toe shows a progressive reduction along the various taxa, culminating in its utter absence in Amphipelargus . Other skeletal remains are rare. Wing elements are known in a few taxa; these are generally highly reduced, suggesting that these birds were flightless. The exception appears to be Eogrus itself, which does not show much phalange reduction and hypothetically could still fly, though
270-456: The order Struthioniformes contained all the ratites. However, recent genetic analysis has found that the group is not monophyletic, as it is paraphyletic with respect to the tinamous , so the ostriches are usually classified as the only members of the order, though the IUCN uses a broader classification and includes all "ratites" and tinamous in Struthioniformes. Struthionidae is a member of
288-498: The rest of the postcranial skeleton is already specialised for cursoriality. Eogruids were formerly considered to be Gruiformes within the crane - limpkin - trumpeter line, Gruoidea, the exception being Olson 1985 which declared them to be stem-ostriches. A study in 2021 based on newly described remains found that eogruids and the related Ergilornithidae are indeed members of Struthoniformes. More derived taxa such as Ergilornis and Amphipelargus were sometimes classified as
306-417: The species S. pannonicus , S. dmanisensis (the giant ostrich), and S. transcaucasicus were transferred to the genus Pachystruthio . Order Struthioniformes Latham 1790 (ostriches) Ergilornithidae Eogruidae (also spelled Eogruiidae in some publications) is a family of large, flightless birds that inhabited Asia from the Eocene to Pliocene epochs. Related to modern ostriches , it
324-423: Was formerly thought to be related to cranes , limpkins and trumpeters and that the similarities with ostriches were due to similar speciations to cursoriality , with both groups showing reduced numbers of toes to two in some taxa. It has been suggested that competition from true ostriches has caused the extinction of these birds, though this has never been formally tested and several ostrich taxa do occur in
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