Tubulidentata - AccessScience from McGraw-Hill Education http://accessscience.com/content/tubulidentata/713700

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Article by: Linzey, Donald W. Wytheville Community College, Wytheville, Virginia. Publication year: 2014 DOI: http://dx.doi.org/10.1036/1097-8542.713700 (http://dx.doi.org/10.1036/1097-8542.713700)

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An order of mammals containing a single living genus Orycteropus, the aardvark. Aardvarks occur in suitable habitats throughout sub-Saharan Africa. This order exhibits the results of an extreme adaptation for burrowing and feeding on small food items (particularly termites and ants). See also: Mammalia (/content/mammalia/402500)

Aardvarks, also known as antbears, resemble a medium-sized to large pig. The body is massive with an elongate head and a piglike snout. The tough thick skin is sparsely covered with bristly hair. The ears are large and donkeylike and can be moved independently of each other. The strong muscular tail is kangaroolike. The short thick legs possess powerful sharp claws that are used to excavate burrows and to open the nests of termites and ants which are gathered by the aardvark's long sticky tongue. Adult aardvarks lack incisor and canine teeth. The simple peglike teeth on the sides of the jaws consist of tubular dentin covered by cement (“tubule teeth”). They lack enamel and grow continuously during the animal's life. The dental formula is I 0/0 C 0/0 Pm 2/2 M 3/3 × 2 for a total of 20 teeth. Adult aardvarks have a head and body length of 1000–1580 mm (39–62 in.), a tail length of 443–710 mm (17–28 in.), and a shoulder height of 600–650 mm (23–25 in.). Most weigh 50–70 kg (110–153 lb). See also: Aardvark (/content/aardvark/000200)

In the past, tubulidentates were often considered closely related to ungulates. However, recent mitochondrial and nuclear gene data show a close relationship to elephant-shrews, paenungulates (hyraxes, sirenians, and proboscideans), and golden moles (Chrysochloridae). All of these ecologically divergent forms probably originated in Africa. Molecular evidence implies that they all may have arisen from a common ancestor that existed in the Cretaceous Period when Africa was isolated from other continents. Three genera of the family Orycteropodidae are known: Leptorycteropus, Myorycteropus, and Orycteropus. The earliest known tubulidentate (Myorycteropus) is from early Miocene deposits found in Kenya in East Africa. Orycteropus gaudryi, a species from the late Miocene epoch, is similar to O. afer except that the former had a greater number of cheekteeth. A relatively unspecialized form, Leptorycteropus, dates from the mid-Pliocene epoch. Pleistocene remains are known from France, Greece, India, and Turkey. A genus from Madagascar (Plesiorycteropus) may be related to them.

Donald W. Linzey

Bibliography

R. L. Carroll, Vertebrate Paleontology and Evolution, Freeman, 1998

D. Macdonald (ed.), The Encyclopedia of Mammals, Andromeda Oxford, 2001

R. M. Nowak, Walker's Mammals of the World, 6th ed., Johns Hopkins University Press, 1999

1 of 3 3/14/2016 10:35 AM Tubulidentata - AccessScience from McGraw-Hill Education http://accessscience.com/content/tubulidentata/713700 Additional Readings

U. Amason, A. Gullberg, and A. Janke, The mitochondrial DNA molecule of the aardvark, Orycteropus afer, and the position of the Tubulidentata in the eutherian tree, Proc. Roy. Soc. London, Ser. B, Biol. Sci., 266(1417):339–345, 1999 DOI: 10.1098/rspb.1999.0643 (http://dx.doi.org/10.1098/rspb.1999.0643)

B. Patterson, The fossil aardvarks (Mammalia: Tubulidentata), Bull. Mus. Comp. Zool., 147:185–237, 1975

J. Shoshani, C. A. Goldman, and J. G. M. Thewissen, Orycteropus afer, Mammal. Species, no. 300, American Society of Mammalogists, 1988

M. S. Springer, Molecular clocks and the timing of the placental and marsupial radiations in relation to the Cretaceous-Tertiary boundary, J. Mammal. Evol., 4:285–301, 1997 DOI: 10.1023/A:1027378615412 (http://dx.doi.org/10.1023/A:1027378615412)

T. A. Vaughan, J. M. Ryan, and N. J. Czaplewski, Mammalogy, 5th ed., Jones & Bartlett Publishers, Sudbury, MA, 2011

J. R. Wible, The ear region of the aardvark, Orycteropus afer (Pallas, 1766) (Mammalia, Placentalia, Tubulidentata), Ann. Carnegie Mus., 80(2):115–146, 2012 DOI: 10.2992/007.080.0202 (http://dx.doi.org/10.2992/007.080.0202)

Animal Diversity Web (http://animaldiversity.ummz.umich.edu/site/accounts/information/Tubulidentata.html)

Tree of Life Web Project (http://tolweb.org/tree?group=Tubulidentata)

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