Xenungulata
| Xenungulata | ||||||||||||
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| Temporal occurrence | ||||||||||||
| Upper Paleocene | ||||||||||||
| 60 to 55 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Xenungulata | ||||||||||||
| Paula Couto , 1952 | ||||||||||||
The Xenungulata are a group of extinct mammals that lived in the Upper Paleocene in South America . Fossil remains have been found in Brazil and Argentina .
General
Xenungulata are among the largest mammals of the Paleocene and were externally possibly tapir-like animals. The body was stocky, the limbs rather short and thin. The legs ended in five broad, hoofed toes. They had large, chisel-like front teeth and broad molars . Only three genera have been described: Carodnia , Etayoa and Notoetayoa .
Systematics
The Xenungulata are closely related to the Pyrotheria , a group of elephant-like animals common in the Eocene and Oligocene , and may even represent their ancestors.
Usually they are considered to be the original representatives of the South American ungulates (Meridiungulata), a widely branched group of mammals from South America that is now extinct. However, some researchers put them together with the Pyrotheria in a close relationship to the Dinocerata , a mammalian order, the best-known representative of which is Uintatherium , which together form the Uintatheriamorpha, however, due to some tooth features . As a rule, however, the Dinocerata and the Xenungulata-Pyrotheria are considered independent, the commonalities of the two groups are seen as a convergent development.
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External and internal systematics of the Xenungulata according to Gelfo et al. 2008
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The internal system according to McKenna & Bell:
- Order Xenungulata Paula Couto , 1952
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- Family Carodniidae Paula Couto , 1952
- Etayoidae Villarroel family , 1987
- Etayoa Villarroel , 1987
- Notoetayoa Gelfo, López & Bond , 2008
literature
- TS Kemp: The Origin & Evolution of Mammals. Oxford University Press, Oxford 2005. ISBN 0198507615
Individual evidence
- ↑ a b c Javier N. Gelfo, Guillermo M. López and Mariano Bond: A New Xenungulata (Mammalia) from the Paleocene of Patagonia, Argentina. Journal of Paleontology 82 (2), pp. 329-335
- ↑ Malcolm C. McKenna and Susan K. Bell: Classification of mammals above the species level. Columbia University Press, New York, 1997, pp. 1-631 (p. 468)
- ↑ Javier N. Gelfo, Daniel A. García-López and Lilian P. Bergqvist: Phylogenetic relationships and palaeobiology of a new xenungulate (Mammalia: Eutheria) from the Palaeogene of Argentina. Journal of Systematic Palaeontology, 2020, doi: 10.1080 / 14772019.2020.1715496