Notoungulata

Notoungulata is an extinct order of mammalian ungulates that inhabited South America from the early Paleocene to the Holocene, living from approximately 61 million to 11,000 years ago.[1] Notoungulates were morphologically diverse, with forms resembling animals as disparate as rabbits and rhinoceroses. Notoungulata are the largest group of South American native ungulates, with over 150 genera in 14 families having been described, divided into two major subgroupings, Typotheria and Toxodontia. Notoungulates first diversified during the Eocene. Their diversity declined during the Late Neogene, with only the large toxodontids persisting until the end of the Pleistocene. Collagen analysis suggests that notoungulates are closely related to litopterns, another group of South American ungulates, and their closest living relatives being perissodactyls (odd-toed ungulates), including rhinoceroses, tapirs and equines. but their relationships to other South American ungulates are uncertain. Several groups of notoungulates separately evolved ever growing teeth like rodents and lagomorphs, a distinction among ungulates only shared with Elasmotherium.

Notoungulata
Temporal range: early Paleocene (Danian)-Holocene
~61–0.011 Ma
Toxodon skeleton.jpg
Skeleton of Toxodon (Toxodontidae)
Propachyrucos ameghinorum AMNH.jpg
Skeleton of Prosotherium (Hegetotheriidae)
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Clade: Panperissodactyla
Order: Notoungulata
Roth 1903
Suborders and families

See text

TaxonomyEdit

 
Restoration of Thomashuxleya, an early Notoungulate (Isotemnidae) from the Eocene (Lutetian) of Argentina

Notoungulata is divided into two major suborders, Typotheria and Toxodontia, alongside some basal groups (Notostylopidae and Henricosborniidae) which are potentially paraphyletic.[2] Due to the isolated nature of South America, many notoungulates evolved along convergent lines into forms that resembled mammals on other continents. Examples of this are Pachyrukhos, a notoungulate that filled an ecological niche similar to those of rabbits and hares, and Homalodotherium, which resembled chalicotheres. The families Interatheriidae, Hegetotheriidae, Mesotheriidae and Toxodontidae separately evolved high crowned (hypsodont) ever-growing teeth.[3] During the Pleistocene, Toxodon was the largest common notoungulate. Most of the group (Mixotoxodon, Piauhytherium and Toxodon being exceptions) became extinct after the landbridge between North and South America formed and allowed North American ungulates to enter South America in the Great American Interchange, and then to out-compete the native fauna.[4][5][6] Mixotoxodon was the only member of the group to be successful in invading Central America and southern North America, reaching as far north as Texas.[7]

 
Skull of Hegetotherium

This order is united with other South American ungulates in the super-order Meridiungulata. The notoungulate and litoptern native ungulates of South America have been shown by studies of collagen and mitochondrial DNA sequences to be a sister group to the perissodactyls, making them true ungulates.[8][9][10] The estimated divergence date is 66 million years ago.[10] This conflicts with the results of some morphological analyses which favoured them as afrotherians. It is in line with some more recent morphological analyses which suggested they were basal euungulates. Panperissodactyla has been proposed as the name of an unranked clade to include perissodactyls and their extinct South American ungulate relatives.[8]

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.[11]

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.[12]

Based on an analysis of 133 morphological characters in 50 notoungulate genera, Billet in 2011 concluded that Homalodotheriidae, Leontiniidae, Toxodontidae, Interatheriidae, Mesotheriidae, and Hegetotheriidae are the only monophyletic families of notoungulates.[13]

PhylogenyEdit

Notoungulata

Henricosbornia

Simpsonotus

Notostylops

Pyrotherium

Toxodontia

Pampahippus

Rhyphodon

Thomashuxleya

Periphragnis

Pleurostylodon

Homalodotheriidae

Asmodeus

Homalodotherium

Leontiniidae

Colpodon

Ancylocoelus

Leontinia

Scarrittia

Eomorphippus

Eurygenium

Rhynchippus

Morphippus

Pascualihippus

Argyrohippus

Toxodontidae

Nesodon

Adinotherium

Posnanskytherium

Hoffstetterius

Toxodon

Typotheria

Colbertia

Oldfieldthomasia

Campanorco

Acropithecus

Ultrapithecus

Interatheriidae

Notopithecus

Federicoanaya

Protypotherium

Miocochilius

Archaeophylus

Plagiarthrus

Interatherium

Cochilius

Eohyrax

Pseudhyrax

Mesotheriidae

Plesiotypotherium

Mesotherium

Trachytherus

Archaeotypotherium

Archaeohyrax

Hegetotheriidae

Prohegetotherium

Hegetotherium

Prosotherium

Paedotherium

Orders and familiesEdit

ReferencesEdit

  1. ^ Zimicz, Ana Natalia; Fernández, Mercedes; Bond, Mariano; Chornogubsky, Laura; Arnal, Michelle; Cárdenas, Magalí; Fernicola, Juan Carlos (November 2020). "Archaeogaia macachaae gen. et sp. nov., one of the oldest Notoungulata Roth, 1903 from the early-middle Paleocene Mealla Formation (Central Andes, Argentina) with insights into the Paleocene-Eocene south American biochronology". Journal of South American Earth Sciences. 103: 102772. Bibcode:2020JSAES.10302772Z. doi:10.1016/j.jsames.2020.102772. S2CID 224862237.
  2. ^ Croft, Darin A.; Gelfo, Javier N.; López, Guillermo M. (2020-05-30). "Splendid Innovation: The Extinct South American Native Ungulates". Annual Review of Earth and Planetary Sciences. 48 (1): 259–290. Bibcode:2020AREPS..48..259C. doi:10.1146/annurev-earth-072619-060126. ISSN 0084-6597.
  3. ^ Gomes Rodrigues, Helder; Herrel, Anthony; Billet, Guillaume (2017-01-31). "Ontogenetic and life history trait changes associated with convergent ecological specializations in extinct ungulate mammals". Proceedings of the National Academy of Sciences. 114 (5): 1069–1074. doi:10.1073/pnas.1614029114. ISSN 0027-8424. PMC 5293108. PMID 28096389.
  4. ^ Webb, S. D. (1976). "Mammalian Faunal Dynamics of the Great American Interchange". Paleobiology. 2 (3): 220–234. doi:10.1017/S0094837300004802. JSTOR 2400220.
  5. ^ Marshall, L. G.; Cifelli, R. L. (1990). "Analysis of changing diversity patterns in Cenozoic land mammal age faunas, South America". Palaeovertebrata. 19: 169–210. Retrieved 2018-10-08.
  6. ^ Webb, S. D. (1991). "Ecogeography and the Great American Interchange". Paleobiology. 17 (3): 266–280. doi:10.1017/S0094837300010605. JSTOR 2400869.
  7. ^ Lundelius, E. L.; Bryant, V. M.; Mandel, R.; Thies, K. J.; Thoms, A. (January 2013). "The first occurrence of a toxodont (Mammalia, Notoungulata) in the United States". Journal of Vertebrate Paleontology. 33 (1): 229–232. doi:10.1080/02724634.2012.711405. hdl:1808/13587. S2CID 53601518.
  8. ^ a b Welker et al. 2015
  9. ^ Buckley 2015
  10. ^ a b Westbury et al. 2017
  11. ^ Cifelli 1993
  12. ^ Missiaen et al. 2006
  13. ^ Billet 2011

BibliographyEdit

Further readingEdit

  • Carroll, Robert Lynn (1988). Vertebrate Paleontology and Evolution. New York: W.H. Freeman and Company. ISBN 9780716718222. OCLC 14967288.
  • McKenna, M.C. (1975). "Toward a phylogenetic classification of the Mammalia". In Luckett, W.P.; Szalay, F.S. (eds.). Phylogeny of the primates: a multidisciplinary approach (Proceedings of WennerGren Symposium no. 61, Burg Wartenstein, Austria, July 6–14, 1974). New York: Plenum. pp. 21–46. doi:10.1007/978-1-4684-2166-8_2. ISBN 978-1-4684-2168-2. OCLC 1693999.
  • McKenna, Malcolm C.; Bell, Susan K. (1997). Classification of Mammals Above the Species Level. New York: Columbia University Press. ISBN 0231110138. OCLC 37345734.