Afrotheria

Afrotheria
Temporal range: Paleocene – Holocene, 65–0 Ma
1. Aardvark 2. Dugong 3. Black and rufous elephant shrew 4. West Indian manatee 5. Cape golden mole 6. Rock hyrax 7. African bush elephant 8. Tailless tenrec
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Placentalia
Superorder: Afrotheria
Stanhope MJ, Waddell VG, Madsen O, de Jong W, Hedges SB, Cleven G, Kao D, Springer MS, 1998
Orders

See below

Afrotheria (/æfroʊˈθɪəriə/ from Latin Afro- "of Africa" + theria "wild beast") is a superorder of placental mammals, the living members of which belong to groups that are either currently living in Africa or of African origin: golden moles, elephant shrews (also known as sengis), otter shrews, tenrecs, aardvarks, hyraxes, elephants, sea cows, and several extinct clades. Most groups of afrotheres share little or no superficial resemblance, and their similarities have only become known in recent times because of genetics and molecular studies. Many afrothere groups are found mostly or exclusively in Africa, reflecting the fact that Africa was an island continent from the Cretaceous until the early Miocene around 20 million years ago, when Afro-Arabia collided with Eurasia.

Because Africa was isolated by water, Laurasian groups of mammals such as insectivores, rodents, lagomorphs, carnivorans and ungulates could not reach Africa for much of the early to mid-Cenozoic. Instead, the niches occupied by those groups on the northern continents were filled by various groups of afrotheres via the process of convergent evolution. The small insectivorous afrotheres such as elephant shrews, golden moles, and tenrecs filled the niches of insectivores, the hyraxes filled the roles of rodents and lagomorphs, the aardvarks filled the roles of various medium size ant-eating mammals (anteaters, armadillos, pangolins, echidnas, numbats, etc.) found on other continents throughout the Cenozoic, and proboscideans (elephants and their relatives) filled the roles of large herbivores such as hippos, camels, rhinos, and tapirs. The sirenians developed aquatic body plans and started spreading to other parts of the world by water (evolving convergently with the other groups of marine mammals such as cetaceans and pinnipeds). In addition to their similarity with Laurasian mammals in North America, Europe, and Asia, many afrotheres also exhibit convergent evolution with groups of mammals that evolved and lived exclusively in South America, which was also an island continent for much of the Cenozoic.

The common ancestry of these animals was not recognized until the late 1990s.[1] Historically, the Paenungulata had been linked to the true ungulates (particularly the perissodactyls); the golden mole, tenrecs, and elephant shrews with the traditional (and polyphyletic/incorrect) taxon Insectivora; and the aardvarks with the pangolins and the xenarthrans within the invalid taxon Edentata. Continuing work on the molecular[2][3][4] and morphological[5][6][7][8] diversity of afrotherian mammals has provided ever increasing support for their common ancestry.

  1. ^ Stanhope, M. J.; Waddell, V. G.; Madsen, O.; de Jong, W.; Hedges, S. B.; Cleven, G. C.; Kao, D.; Springer, M. S. (1998). "Molecular evidence for multiple origins of Insectivora and for a new order of endemic African insectivore mammals". Proceedings of the National Academy of Sciences. 95 (17): 9967–9972. Bibcode:1998PNAS...95.9967S. doi:10.1073/pnas.95.17.9967. PMC 21445. PMID 9707584.
  2. ^ Springer, Mark S.; Michael J. Stanhope; Ole Madsen; Wilfried W. de Jong (2004). "Molecules consolidate the placental mammal tree" (PDF). Trends in Ecology & Evolution. 19 (8): 430–438. doi:10.1016/j.tree.2004.05.006. PMID 16701301. S2CID 1508898.
  3. ^ Robinson, T. J.; Fu, B.; Ferguson-Smith, M. A.; Yang, F. (2004). "Cross-species chromosome painting in the golden mole and elephant-shrew: support for the mammalian clades Afrotheria and Afroinsectiphillia but not Afroinsectivora". Proceedings of the Royal Society B: Biological Sciences. 271 (1547): 1477–1484. doi:10.1098/rspb.2004.2754. PMC 1691750. PMID 15306319.
  4. ^ Nishihara, H.; Satta, Y.; Nikaido, M.; Thewissen, J.G.M.; Stanhope, M.J.; Okada, N. (2005). "A retroposon analysis of Afrotherian phylogeny". Molecular Biology and Evolution. 22 (9): 1823–1833. doi:10.1093/molbev/msi179. PMID 15930154.
  5. ^ Cite error: The named reference Asher et al 2009 was invoked but never defined (see the help page).
  6. ^ Tabuce, R.; Marivaux, L.; Adaci, M.; Bensalah, M.; Hartenberger, J.-L.; Mahboubi, M.; Mebrouk, F.; Tafforeau, P.; Jaeger, J.-J. (2007). "Early Tertiary mammals from North Africa reinforce the molecular Afrotheria clade". Proceedings of the Royal Society B: Biological Sciences. 274 (1614): 1159–1166. doi:10.1098/rspb.2006.0229. PMC 2189562. PMID 17329227.
  7. ^ Cite error: The named reference Seifert2007 was invoked but never defined (see the help page).
  8. ^ Sánchez-Villagra, Marcelo R.; Narita, Yuichi; Kuratani, Shigeru (2007). "Thoracolumbar vertebral number: The first skeletal synapomorphy for afrotherian mammals". Systematics and Biodiversity. 5 (1): 1–7. Bibcode:2007SyBio...5Q...1S. doi:10.1017/S1477200006002258. S2CID 85675984.