Ostrich

Ostrich
Temporal range: MioceneHolocene, 23–0 Ma
Montage of two living species, from left to right: common ostrich and Somali ostrich
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Infraclass: Palaeognathae
Order: Struthioniformes
Family: Struthionidae
Genus: Struthio
Linnaeus, 1758[1]
Type species
Struthio camelus
Linnaeus, 1758
Species
Synonyms
  • Autruchon Temminick 1840 fide Gray, 1841 (nomen nudum)
  • Struthiolithus Brandt 1873
  • Megaloscelornis Lydekker 1879
  • Palaeostruthio Burchak-Abramovich 1953

Ostriches are large flightless birds. Two living species are recognised, the common ostrich, native to large areas of sub-Saharan Africa, and the Somali ostrich, native to the Horn of Africa.

They are the heaviest and largest living birds, with adult common ostriches weighing anywhere between 63.5 and 145 kilograms and laying the largest eggs of any living land animal.[3] With the ability to run at 70 km/h (43.5 mph),[4] they are the fastest birds on land. They are farmed worldwide, with significant industries in the Philippines and in Namibia. South Africa produces about 70% of global ostrich products,[5] with the industry largely centered around the town of Oudtshoorn. Ostrich leather is a lucrative commodity, and the large feathers are used as plumes for the decoration of ceremonial headgear. Ostrich eggs have been used by humans for millennia.

Ostriches are of the genus Struthio in the order Struthioniformes, part of the infra-class Palaeognathae, a diverse group of flightless birds also known as ratites that includes the emus, rheas, cassowaries, kiwis and the extinct elephant birds and moas.

The common ostrich was historically native to the Arabian Peninsula, and ostriches were present across Asia as far east as China and Mongolia during the Late Pleistocene and possibly into the Holocene.

Mating dance of the Ostrich.

Taxonomic history

The genus Struthio was first described by Carl Linnaeus in 1758. The genus was used by Linnaeus and other early taxonomists to include the emu, rhea, and cassowary, until they each were placed in their own genera.[1] The Somali ostrich (Struthio molybdophanes) has recently become recognized as a separate species by most authorities, while others are still reviewing the evidence.[6][7]

Evolution

Struthionidae is a member of 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 is therefore most likely that Struthionidae originated in Asia.[8]

The earliest fossils of the genus Struthio are from the early Miocene ~21 million years ago of Namibia in Africa, so it is proposed that genus is of African origin. By the middle to late Miocene (5–13 mya) they had spread to and become widespread across Eurasia.[9] While the relationship of the African fossil species is comparatively straightforward, many Asian species of ostrich have been described from fragmentary remains, and their interrelationships and how they relate to the African ostriches are confusing. In India, Mongolia and China, ostriches are known to have become extinct only around, or even after, the end of the last ice age; images of ostriches have been found prehistoric Chinese pottery and petroglyphs.[10][11][12][13]

Distribution and habitat

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.[14] The Somali ostrich occurs in the Horn of Africa, having evolved isolated from 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.[15] 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.[16] Escaped common ostriches in Australia have established feral populations.[17][18][19]

Species

A male Somali ostrich in a Kenyan savanna, showing its blueish neck

In 2008, S. linxiaensis was transferred to the genus Orientornis.[20] Three additional species, S. pannonicus, S. dmanisensis, and S. transcaucasicus, were transferred to the genus Pachystruthio in 2019.[21] Several additional fossil forms are ichnotaxa (that is, classified according to the organism's trace fossils such as footprints rather than its body) and their association with those described from distinctive bones is contentious and in need of revision pending more good material.[22]

The species are:

Citations

  1. ^ a b Gray, George Robert (1855). Catalogue of the Genera and Subgenera of Birds contained in the British Museum. London, UK: Taylor and Francis. p. 109.
  2. ^ BirdLife International (2018). "Struthio camelus". IUCN Red List of Threatened Species. 2018: e.T45020636A132189458. doi:10.2305/IUCN.UK.2018-2.RLTS.T45020636A132189458.en. Retrieved 29 February 2024.
  3. ^ Del Hoyo, Josep, et al. Handbook of the birds of the world. Vol. 1. No. 8. Barcelona: Lynx edicions, 1992.
  4. ^ Doherty, James G. (March 1974). "Speed of animals". Natural History.
  5. ^ Western Cape Department of Agriculture (July 2020). "The South African Ostrich Industry Footprint" (PDF). Retrieved 20 May 2024.
  6. ^ Gill, F.; Donsker, D (2012). "Ratites". IOC World Bird List. WorldBirdNames.org. Retrieved 13 Jun 2012.
  7. ^ BirdLife International (2012). "The BirdLife checklist of the birds of the world, with conservation status and taxonomic sources". Archived from the original (xls) on 25 December 2011. Retrieved 16 Jun 2012.
  8. ^ Mayr, Gerald; Zelenkov, Nikita (2021-11-13). "Extinct crane-like birds (Eogruidae and Ergilornithidae) from the Cenozoic of Central Asia are indeed ostrich precursors". Ornithology. 138 (4): ukab048. doi:10.1093/ornithology/ukab048. ISSN 0004-8038.
  9. ^ Mikhailov, Konstantin E.; Zelenkov, Nikita (September 2020). "The late Cenozoic history of the ostriches (Aves: Struthionidae), as revealed by fossil eggshell and bone remains". Earth-Science Reviews. 208: 103270. Bibcode:2020ESRv..20803270M. doi:10.1016/j.earscirev.2020.103270. S2CID 225275210.
  10. ^ Doar, B.G. (2007) "Genitalia, Totems and Painted Pottery: New Ceramic Discoveries in Gansu and Surrounding Areas" Archived 2020-09-23 at the Wayback Machine. China Heritage Quarterly
  11. ^ a b Janz, Lisa; et al. (2009). "Dating North Asian surface assemblages with ostrich eggshell: Implications for palaeoecology and extirpation". Journal of Archaeological Science. 36 (9): 1982–1989. doi:10.1016/j.jas.2009.05.012.
  12. ^ a b Andersson, Johan Gunnar (1923). On the occurrence of fossil remains of Struthionidae in China. In: Essays on the cenozoic of northern China. Memoirs of the Geological Survey of China (Peking), Series A, No. 3, pp. 53–77. Peking, China: Geological Survey of China.
  13. ^ Jain, Sonal; Rai, Niraj; Kumar, Giriraj; Pruthi, Parul Aggarwal; Thangaraj, Kumarasamy; Bajpai, Sunil; Pruthi, Vikas (2017-03-08). Calafell, Francesc (ed.). "Ancient DNA Reveals Late Pleistocene Existence of Ostriches in Indian Sub-Continent". PLOS ONE. 12 (3): e0164823. Bibcode:2017PLoSO..1264823J. doi:10.1371/journal.pone.0164823. ISSN 1932-6203. PMC 5342186. PMID 28273082.
  14. ^ Donegan, Keenan (2002). "Struthio camelus". Animal Diversity Web. University of Michigan Museum of Zoology.
  15. ^ Freitag, Stephanie & Robinson, Terence J. (1993). "Phylogeographic patterns in mitochondrial DNA of the Ostrich (Struthio camelus)" (PDF). The Auk. 110 (3): 614–622. doi:10.2307/4088425. JSTOR 4088425.
  16. ^ Rinat, Zafrir (25 December 2007). "The Bitter Fate of Ostriches in the Wild". Haaretz. Tel Aviv. Retrieved 10 January 2017.
  17. ^ Ostriches in Australia – and near my home Archived 2020-06-11 at the Wayback Machine. trevorsbirding.com (13 September 2007)
  18. ^ Rural, A. B. C. (2018-09-01). "The outback ostriches — Australia's loneliest birds". ABC News. Retrieved 2021-02-10.
  19. ^ "Common Ostrich (Struthio camelus)". iNaturalist Australia. Retrieved 2021-02-10.
  20. ^ Wang, S. (2008). "Rediscussion in the taxonomic assignment of Struthio linxiaensis Hou, et al., 2005". Acta Paleotologica Sinica. 47: 362–368.
  21. ^ Zelenkov, N. V.; Lavrov, A. V.; Startsev, D. B.; Vislobokova, I. A.; Lopatin, A. V. (2019). "A giant early Pleistocene bird from eastern Europe: unexpected component of terrestrial faunas at the time of early Homo arrival". Journal of Vertebrate Paleontology. 39 (2): e1605521. doi:10.1080/02724634.2019.1605521. S2CID 198384367.
  22. ^ Bibi, Faysal; Shabel, Alan B.; Kraatz, Brian P.; Stidham, Thomas A. (2006). "New Fossil Ratite (Aves: Palaeognathae) Eggshell Discoveries from the Late Miocene Baynunah Foramation of the United Arab Emirates, Arabian Peninsula" (PDF). Palaeontologia Electronica. 9 (1): 2A. ISSN 1094-8074.
  23. ^ "OVPP-Struthio 8". olduvai-paleo.org.
  24. ^ Andersson, Johan Gunnar (1943). "Research into the prehistory of the Chinese". Bulletin of the Museum of Far Eastern Antiquities. 15: 1–300.

General references