Notoungulata
Encyclopedia
Notoungulata is an extinct order of hoofed, sometimes heavy bodied mammal
ian ungulate
s which inhabited South America
during the Paleocene
to Pleistocene
, living from approximately 57 Ma to 11,000 years ago.
into forms that resembled mammals on other continents. Examples of this are Pachyrukhos
, a notoungulate that evolved to fill the role of rabbits and hares and Homalodotherium
, which evolved to resemble chalicothere
s. During the Pleistocene
, Toxodon
was the largest common notoungulate. Most of the group (Toxodon being an exception) became extinct after the landbridge between North and South America was formed, allowing North American ungulates to enter South America in the Great American Interchange
and out-compete the native fauna. This order is united with other South-American ungulates in the super-order Meridiungulata
.
Cifelli has argued that Notioprogonia is paraphyletic, as it would include the ancestors of the remaining suborders. Similarly, Cifelli indicated that Typotheria would be paraphyletic if it excluded Hegetotheria and he advocated inclusion of Archaeohyracidae and Hegetotheriidae in Typotheria.
As reflected in the map that accompanies this article, Notoungulata were for many years taken to include the order Arctostylopida
, whose fossils are found mainly in China. Recent studies, however, have concluded that Arctostylopida are more properly classified as gliriforms
, and that the notoungulates were therefore never found outside South and Central America.
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
ian ungulate
Ungulate
Ungulates are several groups of mammals, most of which use the tips of their toes, usually hoofed, to sustain their whole body weight while moving. They make up several orders of mammals, of which six to eight survive...
s which inhabited South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
during the Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...
to Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, living from approximately 57 Ma to 11,000 years ago.
Taxonomy
Notoungulata was named by Roth (1903). It was assigned to Eutheria by Carroll (1988). Due to the isolated nature of South America, many notoungulates evolved along convergent linesConvergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
into forms that resembled mammals on other continents. Examples of this are Pachyrukhos
Pachyrukhos
Pachyrukhos is an extinct genus of mammal from the Oligocene and Miocene of South America.It was about 30 cm long and closely resembled a rabbit, possessing a short tail and long hind feet. Pachyrukhos was probably also able to hop, and it had a rabbit-like skull with teeth adapted for eating nuts...
, a notoungulate that evolved to fill the role of rabbits and hares and Homalodotherium
Homalodotherium
Homalodotherium is an extinct genus of the order Notoungulata, an extinct group of hoofed mammals native to South America.Homalodotherium was about in body length, and had long forelimbs with claws instead of hooves...
, which evolved to resemble chalicothere
Chalicothere
Chalicotheres were a group of herbivorous, odd-toed ungulate mammals spread throughout North America, Europe, Asia, and Africa during the Early Eocene to Early Pleistocene subepochs living from 55.8 mya—781,000 years ago, existing for approximately .They evolved around 40 million years ago from...
s. During the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, Toxodon
Toxodon
Toxodon is an extinct mammal of the late Pliocene and Pleistocene epochs about 2.6 million to 16,500 years ago. It was indigenous to South America, and was probably the most common large-hoofed mammal in South America at the time of its existence....
was the largest common notoungulate. Most of the group (Toxodon being an exception) became extinct after the landbridge between North and South America was formed, allowing North American ungulates to enter South America in the Great American Interchange
Great American Interchange
The Great American Interchange was an important paleozoogeographic event in which land and freshwater fauna migrated from North America via Central America to South America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the formerly separated continents...
and out-compete the native fauna. This order is united with other South-American ungulates in the super-order Meridiungulata
Meridiungulata
Meridiungulata is an extinct clade with the rank of cohort or super-order, containing the South-American ungulates: Pyrotheria , Astrapotheria, Notoungulata and Litopterna...
.
Cifelli has argued that Notioprogonia is paraphyletic, as it would include the ancestors of the remaining suborders. Similarly, Cifelli indicated that Typotheria would be paraphyletic if it excluded Hegetotheria and he advocated inclusion of Archaeohyracidae and Hegetotheriidae in Typotheria.
As reflected in the map that accompanies this article, Notoungulata were for many years taken to include the order Arctostylopida
Arctostylopida
Arctostylopida is an extinct order of placental mammals. They're animals of uncertain affinities to other groups and it was believed that they may be related to ungulates. Originally they were considered to be Northern relatives of Southern American notoungulates, closer to Notostylopidae...
, whose fossils are found mainly in China. Recent studies, however, have concluded that Arctostylopida are more properly classified as gliriforms
Glires
Glires is a clade consisting of rodents and lagomorphs . This hypothesis that these form a monophyletic group has been long debated based on morphological evidence, although recent morphological studies strongly support monophyly of Glires...
, and that the notoungulates were therefore never found outside South and Central America.
Orders and families
- Order Notoungulata - notoungulates
- Suborder NotioprogoniaNotioprogoniaNotioprogonia is a suborder of the extinct mammalian order Notoungulata and includes two families, Henricosborniidae and Notostylopidae. Notioprogonia includes the most primitive notoungulates and has argued that Notioprogonia is paraphyletic because it would include the ancestors of the remaining...
- Family HenricosborniidaeHenricosborniidaeHenricosborniidae is an extinct family comprising four genera of notoungulate mammals known from the Paleocene and early Eocene of South America....
- Family NotostylopidaeNotostylopidaeNotostylopidae is an extinct family comprising five genera of notoungulate mammals known from the early Eocene to early Oligocene of South America...
- Family Henricosborniidae
- Suborder ToxodontaToxodontaToxodonta is a suborder of the extinct mammalian order Notoungulata. The group is named after Toxodon, the first example of the group to be discovered. The suborder includes the largest known notoungulates, members of the family Toxodontidae. Toxodontids first appeared during the Oligocene in the...
- Family IsotemnidaeIsotemnidaeIsotemnidae is an extinct family of notoungulate mammals known from the Paleocene through Oligocene of South America....
- Family LeontiniidaeLeontiniidaeLeontiniidae is an extinct family comprising six genera of notoungulate mammals known from the middle Eocene through middle Miocene of South America .-References:...
- Family NotohippidaeNotohippidaeNotohippidae is an extinct family of notoungulate mammals from South America. Notohippids are known from the Eocene and Oligocene epochs....
- Family ToxodontidaeToxodontidaeToxodontidae is an extinct family of notoungulate mammals known from the Oligocene through the Pleistocene of South America, with one genus, Mixotoxodon, also known from the Pleistocene of Central America. They somewhat resembled rhinoceroses, and had teeth with high crowns and open roots,...
- Family HomalodotheriidaeHomalodotheriidaeHomalodotheriidae is an extinct family comprising four genera of notoungulate mammals known from the late Eocene through late Miocene of South America....
- Family Isotemnidae
- Suborder TypotheriaTypotheriaTypotheria is a suborder of the extinct mammalian order Notoungulata and includes five families: Archaeopithecidae, Campanorcidae, Interatheriidae, Mesotheriidae, and Oldfieldthomasiidae...
- Family ArchaeopithecidaeArchaeopithecidaeArchaeopithecidae is an extinct family comprising two genera of notoungulate mammals, Acropithecus and Archaeopithecus, both known from the early Eocene of South America .-References:...
- Family OldfieldthomasiidaeOldfieldthomasiidaeOldfieldthomasiidae is an extinct family of notoungulate mammals known from the Paleocene and Eocene of South America....
- Family InteratheriidaeInteratheriidaeInteratheriidae is an extinct family of notoungulate mammals from South America. Interatheriids are known from the Paleocene or Eocene through the Miocene .-References:...
- Family CampanorcidaeCampanorcoCampanorco is an extinct genus of notoungulate mammal from the early Eocene of South America and the only member of the family Campanorcidae .-References:...
- Family MesotheriidaeMesotheriidaeMesotheriidae is an extinct family of notoungulate mammals known from the Eocene through the Pleistocene of South America. Mesotheriids were small to medium-sized herbivorous mammals adapted for digging.-Characteristics:...
- Family Archaeopithecidae
- Suborder HegetotheriaHegetotheriaHegetotheria is a suborder of the extinct mammalian order Notoungulata and includes two families, Archaeohyracidae and Hegetotheriidae. Cifelli indicated that the suborder Typotheria would be paraphyletic if it excluded members of Hegetotheria and he advocated inclusion of the hegetothere families...
- Family ArchaeohyracidaeArchaeohyracidaeArchaeohyracidae is an extinct family comprising four genera of notoungulate mammals known from the Paleocene through the Oligocene of South America....
- Family HegetotheriidaeHegetotheriidaeHegetotheriidae is an extinct family of notoungulate mammals known from the Eocene through the Pleistocene of South America...
- Family Archaeohyracidae
- Suborder Notioprogonia
Notations
- McKenna, Malcolm C., and Bell, Susan K. 1997. Classification of Mammals Above the Species Level. Columbia University Press, New York, 631 pp. ISBN 0-231-11013-8