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 (Deseadan)-Holocene ~23–0.011 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Mixotoxodon larensis
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	†Notoungulata
Family:	†Toxodontidae Owen 1845
Subfamilies and genera
†Haplodontheriinae †Abothrodon †Haplodontherium †Mesotoxodon †Mixotoxodon †Ocnerotherium †Pachynodon †Paratrigodon †Prototrigodon †Toxodontherium †Trigodon †Trigodonops †Nesodontinae †Adinotherium †Nesodon †Palyeidodon †Posnanskytherium †Proadinotherium †Toxodontinae †Andinotoxodon †Ceratoxodon †Chapalmalodon †Dinotoxodon †Eutomodus †Gyrinodon †Hemixotodon †Hyperotoxodon †Mesenodon †Minitoxodon †Neoadinotherium †Neotoxodon †Nesodonopsis †Nonotherium †Pericotoxodon †Piauhytherium †Pisanodon †Plesiotoxodon †Stenotephanos †Stereotoxodon †Toxodon †Xotodon

Xotodon sp. skull at the Museum für Naturkunde, Berlin

Taxonomy

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.       Scarritia 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

References

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 reading

• 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