Proboscidea

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Proboscidea
Temporal range: Middle Paleocene-Holocene 60.0–0 Ma
AfricanElephant.jpg
African bush elephant, Loxodonta africana
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Clade: Tethytheria
Order: Proboscidea
Illiger, 1811
Subclades

The Proboscidea (/prɒbəˈsɪdə/, from the Greek προβοσκίς and the Latin proboscis) are a taxonomic order of afrotherian mammals containing one living family (Elephantidae) and several extinct families. First described by J. Illiger in 1811, it encompasses the elephants and their close relatives.[1] From the mid-Miocene onwards, most proboscideans were very large. The largest land mammal of all time may have been a proboscidean; Palaeoloxodon namadicus was up to 5.2 m (17.1 ft) at the shoulder and may have weighed up to 22 t (24.3 short tons), almost double the weight of some sauropods like Diplodocus carnegii.[2] The largest extant proboscidean is the African bush elephant, with a record of size of 4 m (13.1 ft) at the shoulder and 10.4 t (11.5 short tons).[2] In addition to their enormous size, later proboscideans are distinguished by tusks and long, muscular trunks, which were less developed or absent in early proboscideans.

Elephants are the largest existing land animals. Three species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. Elephantidae is the only surviving family of the order Proboscidea; extinct members include the mastodons. The family Elephantidae also contains several extinct groups, including the mammoths and straight-tusked elephants. African elephants have larger ears and concave backs, whereas Asian elephants have smaller ears, and convex or level backs. Distinctive features of all elephants include a long proboscis called a trunk, tusks, large ear flaps, massive legs, and tough but sensitive skin. The trunk is used for breathing, bringing food and water to the mouth, and grasping objects. Tusks, which are derived from the incisor teeth, serve both as weapons and as tools for moving objects and digging. The large ear flaps assist in maintaining a constant body temperature as well as in communication. The pillar-like legs carry their great weight.

Evolution[edit]

The earliest known proboscidean is Eritherium,[3] followed by Phosphatherium,[4] a small animal about the size of a fox. Both date from late Paleocene deposits of Morocco.

Proboscideans evolved in Africa,[5] where they increased in size and diversity during the Eocene and early Oligocene. Proboscideans have evolved greatly over time through three major forms of radiation: radiation of primitive Lophodont forms, radiation of gomphotheres and stegodons, and radiation of elepphantidae. These forms of radiation have illustrated that proboscideans characteristics such as trunk, large ears, tusks, flaps, and huge ears have evolved and were appearing late in the modern form. Several primitive families from these epochs have been described, including the Numidotheriidae, Moeritheriidae, and Barytheriidae, all found exclusively in Africa. The Anthracobunidae from the Indian subcontinent were also believed to be a family of proboscideans, but were excluded from the Proboscidea by Shoshani and Tassy (2005)[6] and have more recently been assigned to the Perissodactyla.[7] When Africa became connected to Europe and Asia after the shrinking of the Tethys Sea, proboscideans migrated into Eurasia, with some families eventually reaching the Americas. Proboscideans found in Eurasia as well as Africa include the Deinotheriidae, which thrived during the Miocene and into the early Quaternary, Stegolophodon, an early genus of the disputed family Stegodontidae; the highly diverse Gomphotheriidae and Amebelodontidae; and the Mammutidae, or mastodons.

Most proboscideans are now extinct,[8] including all species endemic to the Americas, Europe, and northern Asia. Many of these extinctions occurred during or shortly after the last glacial period. Recently extinct species include the gomphotheres in the Americas, the American mastodon of family Mammutidae in North America, numerous stegodonts in Asia, the mammoths throughout the Northern Hemisphere, and several species of dwarf elephants found on various islands scattered around the world.[9]

Classification[edit]

Below is an unranked taxonomy of proboscidean genera as of 2019.[6][10][11][12]

References[edit]

  1. ^ Illiger, Johann Karl Wilhelm (1811). Prodromus Systematis Mammalium et Avium: Additis Terminis Zoographicis Utriusque Classis, Eorumque Versione Germanica. Berolini: Sumptibus C. Salfeld. p. 62.
  2. ^ a b Larramendi, A. (2016). "Shoulder height, body mass and shape of proboscideans" (PDF). Acta Palaeontologica Polonica. 61. doi:10.4202/app.00136.2014. S2CID 2092950.
  3. ^ Gheerbrant, E. (2009). "Paleocene emergence of elephant relatives and the rapid radiation of African ungulates". Proceedings of the National Academy of Sciences. 106 (26): 10717–10721. Bibcode:2009PNAS..10610717G. doi:10.1073/pnas.0900251106. PMC 2705600. PMID 19549873.
  4. ^ Gheebrant, Emmanuel (1996). "A Palaeocene proboscidean from Morocco". Nature. 383 (6595): 68–70. Bibcode:1996Natur.383...68G. doi:10.1038/383068a0. S2CID 4362199.
  5. ^ Cantalapiedra, Juan L.; Sanisdro, Oscar L.; Zhang, Hanwen; Alberdi, Mª Teresa; Prado, Jose Luis; Blanco, Fernando; Saarinen, Juha (1 July 2021). "The rise and fall of proboscidean ecological diversity". Nature Ecology & Evolution. 355 (9): 1266–1272. doi:10.1038/s41559-021-01498-w. PMID 34211141. Retrieved 21 August 2021 – via Escience.magazine.org.
  6. ^ a b Shoshani, Jeheskel; Pascal Tassy (2005). "Advances in proboscidean taxonomy & classification, anatomy & physiology, and ecology & behavior". Quaternary International. 126–128: 5–20. Bibcode:2005QuInt.126....5S. doi:10.1016/j.quaint.2004.04.011.
  7. ^ Cooper, L. N.; Seiffert, E. R.; Clementz, M.; Madar, S. I.; Bajpai, S.; Hussain, S. T.; Thewissen, J. G. M. (8 October 2014). "Anthracobunids from the Middle Eocene of India and Pakistan Are Stem Perissodactyls". PLOS ONE. 9 (10): e109232. Bibcode:2014PLoSO...9j9232C. doi:10.1371/journal.pone.0109232. PMC 4189980. PMID 25295875.
  8. ^ Cantalapiedra, Juan L.; Sanisdro, Oscar L.; Zhang, Hanwen; Alberdi, Mª Teresa; Prado, Jose Luis; Blanco, Fernando; Saarinen, Juha (1 July 2021). "The rise and fall of proboscidean ecological diversity". Nature Ecology & Evolution. 355 (9): 1266–1272. doi:10.1038/s41559-021-01498-w. PMID 34211141. Retrieved 21 August 2021 – via Escience.magazine.org.
  9. ^ Bjorn Kurten, Elaine Anderson (17 May 2005). Pleistocene mammals of North America - Google Books. ISBN 9780231516969. Retrieved 1 July 2009.
  10. ^ Wang, Shi-Qi; Deng, Tao; Ye, Jie; He, Wen; Chen, Shan-Qin (2017). "Morphological and ecological diversity of Amebelodontidae (Proboscidea, Mammalia) revealed by a Miocene fossil accumulation of an upper-tuskless proboscidean". Journal of Systematic Palaeontology. 15 (8): 601–615. doi:10.1080/14772019.2016.1208687. S2CID 89063787.
  11. ^ Mothé, Dimila; Ferretti, Marco P.; Avilla, Leonardo S. (12 January 2016). "The Dance of Tusks: Rediscovery of Lower Incisors in the Pan-American Proboscidean Cuvieronius hyodon Revises Incisor Evolution in Elephantimorpha". PLOS ONE. 11 (1): e0147009. Bibcode:2016PLoSO..1147009M. doi:10.1371/journal.pone.0147009. PMC 4710528. PMID 26756209.
  12. ^ Tabuce, Rodolphe; Sarr, Raphaël; Adnet, Sylvain; Lebrun, Renaud; Lihoreau, Fabrice; Martin, Jeremy; Sambou, Bernard; Thiam, Mustapha; Hautier, Lionel (2019). "Filling a gap in the proboscidean fossil record: a new genus from the Lutetian of Senegal" (PDF). Journal of Paleontology. 94 (3): 580–588. doi:10.1017/jpa.2019.98. S2CID 213978026.

Bibliography[edit]