Toxodontidae

Toxodontidae is an extinct family of notoungulate mammals, known from the Oligocene to the Holocene (11,000 BP) of South America,[1] with one genus, Mixotoxodon, also known from the Pleistocene of Central America and southwestern North America (Texas).[2] They somewhat resembled rhinoceroses, and had teeth with high crowns and open roots, suggesting that they often fed on tough pampas grass.[3] However, isotopic analyses have led to the conclusion that the most recent forms were grazing and browsing generalists.[4]

Toxodontidae
Temporal range: Late Oligocene-Holocene (Deseadan-Lujanian)
~27–0.011 Ma
Mixotoxodon.jpg
Mixotoxodon larensis
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Notoungulata
Clade: Eutoxodontia
Family: Toxodontidae
Owen 1845
Subfamilies and genera

Haplodontheriinae

Nesodontinae

Toxodontinae

Xotodon sp. skull at the Museum für Naturkunde, Berlin

TaxonomyEdit

The endemic notoungulate and litoptern ungulates of South America have been shown by studies of collagen and mitochondrial DNA sequences to be a sister group to the perissodactyls.[5][6][7]

In 2014, a study identifying a new species of toxodontid resolved the families phylogenetic relations. The below cladogram was found by the study:[8]

Pampahippus arenalesi

Rhynchippus spp.

Scarrittia canquelensis

Leonitinia gaudri

Toxodontidae

Proadinotherium leptognathum

Adinotherium spp.

Nesodon taweretus

Nesodon imbricatus

Palyeidodon obtusum

Hyperoxotodon speciosus

Nonotherium henningi

Xotodon spp.

Andinotoxodon bolivariensis

Dinotoxodon paranensis

Toxodon platensis

Gyrinodon quassus

Ocnerotherium intermedium

Hoffstetterius imperator

Posnanskytherium desaguaderoi

Pisanodon nazari

Pericotoxodon platignathus

Calchaquitherium mixtum

Mixotoxodon larensis

Paratrigodon euguii

Trigodon gaudri

ReferencesEdit

  1. ^ Turvey, Samuel T. (2009-05-28). Holocene Extinctions. OUP Oxford. ISBN 9780191579981.
  2. ^ E. Lundelius, et al. 2013. The first occurrence of a toxodont (Mammalia, Notoungulata) in the United States. Journal of Vertebrate Paleontology, Vol 33, No 1, pp. 229–232 DOI:10.1080/02724634.2012.711405
  3. ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 253. ISBN 978-1-84028-152-1.
  4. ^ MacFadden, Bruce J. (September 2005). "Diet and habitat of toxodont megaherbivores (Mammalia, Notoungulata) from the late Quaternary of South and Central America". Quaternary Research. 64 (2): 113–124. Bibcode:2005QuRes..64..113M. doi:10.1016/j.yqres.2005.05.003.
  5. ^ Welker, F.; Collins, M. J.; Thomas, J. A.; Wadsley, M.; Brace, S.; Cappellini, E.; Turvey, S. T.; Reguero, M.; Gelfo, J. N.; Kramarz, A.; Burger, J.; Thomas-Oates, J.; Ashford, D. A.; Ashton, P. D.; Rowsell, K.; Porter, D. M.; Kessler, B.; Fischer, R.; Baessmann, C.; Kaspar, S.; Olsen, J. V.; Kiley, P.; Elliott, J. A.; Kelstrup, C. D.; Mullin, V.; Hofreiter, M.; Willerslev, E.; Hublin, J.-J.; Orlando, L.; Barnes, I.; MacPhee, R. D. E. (2015-03-18). "Ancient proteins resolve the evolutionary history of Darwin's South American ungulates". Nature. 522 (7554): 81–84. Bibcode:2015Natur.522...81W. doi:10.1038/nature14249. ISSN 0028-0836. PMID 25799987. S2CID 4467386.
  6. ^ Buckley, M. (2015-04-01). "Ancient collagen reveals evolutionary history of the endemic South American 'ungulates'". Proceedings of the Royal Society B: Biological Sciences. 282 (1806): 20142671. doi:10.1098/rspb.2014.2671. PMC 4426609. PMID 25833851.
  7. ^ Westbury, M.; Baleka, S.; Barlow, A.; Hartmann, S.; Paijmans, J. L. A.; Kramarz, A.; Forasiepi, A. M.; Bond, M.; Gelfo, J. N.; Reguero, M. A.; López-Mendoza, P.; Taglioretti, M.; Scaglia, F.; Rinderknecht, A.; Jones, W.; Mena, F.; Billet, G.; de Muizon, C.; Aguilar, J. L.; MacPhee, R. D. E.; Hofreiter, M. (2017-06-27). "A mitogenomic timetree for Darwin's enigmatic South American mammal Macrauchenia patachonica". Nature Communications. 8: 15951. Bibcode:2017NatCo...815951W. doi:10.1038/ncomms15951. PMC 5490259. PMID 28654082.
  8. ^ Forasiepi, A. A. M.; Cerdeño, E.; Bond, M.; Schmidt, G. I.; Naipauer, M.; Straehl, F. R.; Martinelli, A. N. G.; Garrido, A. C.; Schmitz, M. D.; Crowley, J. L. (2014). "New toxodontid (Notoungulata) from the Early Miocene of Mendoza, Argentina". Paläontologische Zeitschrift. 89 (3): 611–634. doi:10.1007/s12542-014-0233-5. S2CID 129293436.

Further readingEdit

  • 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

External linksEdit