{{Short description|Extinct family of notoungulate mammals}} {{Automatic taxobox | fossil_range = Late Oligocene-Holocene (Deseadan-Lujanian)<br />~{{Fossil range|27|0.011}} | image = Em - Toxodon platensis - 1.jpg | image_caption = ''Toxodon platensis'' | image2 = Nesodon imbricatus skeleton reconstruction.jpg | image2_caption = Skeleton of ''Nesodon imbricatus'' | taxon = Toxodontidae | subdivision_ranks = Subfamilies and genera | subdivision = †Haplodontheriinae * †''Abothrodon'' * †''Haplodontherium'' * †''Mesotoxodon'' * †''Ocnerotherium'' * †''Toxodontherium'' †Nesodontinae * †''Adinotherium'' * †''Nesodon'' * †''Palyeidodon'' * †''Posnanskytherium'' * †''Proadinotherium'' †Toxodontinae * †''Andinotoxodon'' * †''Ceratoxodon'' * †''Charruatoxodon'' * †''Chapalmalodon'' * †''Dinotoxodon'' * †''Eutomodus'' * †''Falcontoxodon'' * †''Gyrinodon'' * †''Hemixotodon'' * †''Hyperoxotodon'' * †''Mesenodon'' * †''Minitoxodon'' * †''Mixotoxodon'' * †''Neoadinotherium'' * †''Neotoxodon'' * †''Nesodonopsis'' * †''Nonotherium'' * †''Paratrigodon'' * †''Pericotoxodon'' * †''Piauhytherium'' * †''Pisanodon'' * †''Plesiotoxodon'' * †''Prototrigodon'' * †''Stenotephanos'' * †''Stereotoxodon'' * †''Toxodon'' * †''Trigodon'' * †''Trigodonops'' * †''Xotodon'' | authority = Owen, 1845 }} thumb|right|''Xotodon sp.'' skull at the Museum für Naturkunde, Berlin
'''Toxodontidae''' (from Ancient Greek τόξον (''tóxon''), meaning "bow", and ὀδούς (''odoús''), meaning "tooth") is an extinct family of notoungulate mammals, known from the Oligocene to the Holocene (11,000 BP) of South America,<ref>{{Cite book|url=https://books.google.com/books?id=mbU-F42JU1AC&dq=Propaopus&pg=PA349|title=Holocene Extinctions|last1=Turvey|first1=Samuel T.|date=28 May 2009|publisher=OUP Oxford|isbn=978-0-19-157998-1|language=en}}</ref> with one genus, ''Mixotoxodon'', also known from the Pleistocene of Central America and southern North America (as far north as Texas).<ref>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 [https://dx.doi.org/10.1080/02724634.2012.711405 DOI:10.1080/02724634.2012.711405]</ref> Member of the family were medium to large-sized,<ref>{{Cite journal |last1=Cassini |first1=Guillermo H. |last2=Flores |first2=David A. |last3=Vizcaíno |first3=Sergio F. |date=July 2012 |title=Postnatal ontogenetic scaling of Nesodontine (Notoungulata, Toxodontidae) cranial morphology: Nesodontine cranial allometry |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1463-6395.2011.00501.x |journal=Acta Zoologica |language=en |volume=93 |issue=3 |pages=249–259 |doi=10.1111/j.1463-6395.2011.00501.x|hdl=11336/81335 |hdl-access=free }}</ref> ranging from around {{Convert|350–400|kg|lb}} in ''Nesodon'' to {{Convert|1000–1200|kg|lb}} in ''Toxodon'',<ref>{{Cite journal |last1=Nelson |first1=Allison |last2=Engelman |first2=Russell K. |last3=Croft |first3=Darin A. |date=12 July 2023 |title=How to weigh a fossil mammal? South American notoungulates as a case study for estimating body mass in extinct clades |url=https://link.springer.com/10.1007/s10914-023-09669-1 |journal=Journal of Mammalian Evolution |language=en |doi=10.1007/s10914-023-09669-1 |issn=1064-7554|url-access=subscription }}</ref> and had medium to high-crowned dentition, which in derived members of the group evolved into ever-growing cheek teeth.<ref>{{Cite journal |last1=Gomes Rodrigues |first1=Helder |last2=Herrel |first2=Anthony |last3=Billet |first3=Guillaume |date=31 January 2017 |title=Ontogenetic and life history trait changes associated with convergent ecological specializations in extinct ungulate mammals |journal=Proceedings of the National Academy of Sciences of the United States of America |language=en |volume=114 |issue=5 |pages=1069–1074 |doi=10.1073/pnas.1614029114 |issn=0027-8424 |pmc=5293108 |pmid=28096389 |doi-access=free}}</ref>
== Palaeobiology ==
=== Palaeoecology === Isotopic analyses have led to the conclusion that Pleistocene members of the family were flexible mixed feeders (both browsing and grazing).<ref name = "MacFadden">{{Cite journal | last1 = MacFadden | first1 = Bruce J. | title = Diet and habitat of toxodont megaherbivores (Mammalia, Notoungulata) from the late Quaternary of South and Central America | journal = Quaternary Research | volume = 64 | issue = 2 | pages = 113–124 | date = September 2005 | doi = 10.1016/j.yqres.2005.05.003 |bibcode = 2005QuRes..64..113M }}</ref><ref>{{Cite journal |last1=Pérez-Crespo |first1=Víctor Adrián |last2=Arroyo-Cabrales |first2=Joaquín |last3=Guzmán |first3=Ana Fabiola |last4=Morales-Puente |first4=Pedro |last5=Cienfuegos-Alvarado |first5=Edith |last6=Otero |first6=Francisco J. |date=2020-01-09 |title=ISOTOPIC PALEOECOLOGY OF A TOXODONT (MIXOTOXODON LARENSIS) FROM MICHOACAN, MEXICO |url=https://bioone.org/journals/the-southwestern-naturalist/volume-64/issue-1/0038-4909-64-1-63/ISOTOPIC-PALEOECOLOGY-OF-A-TOXODONT-MIXOTOXODON-LARENSIS-FROM-MICHOACAN-MEXICO/10.1894/0038-4909-64-1-63.full |journal=The Southwestern Naturalist |volume=64 |issue=1 |page=63 |doi=10.1894/0038-4909-64-1-63 |issn=0038-4909|url-access=subscription }}</ref> The family's dietary ecology shifted over time; δ<sup>13</sup>C ratios show them being mainly browsers in the Miocene and becoming increasingly grazing animals during the Pliocene and especially the Pleistocene epochs.<ref>{{Cite journal |last1=Sanz-Pérez |first1=Dánae |last2=Tomassini |first2=Rodrigo L. |last3=Montalvo |first3=Claudia I. |last4=Zurita |first4=Alfredo |last5=Hernández Fernández |first5=Manuel |last6=Domingo |first6=Laura |date=31 May 2024 |title=Stable isotope analysis evidences dietary changes in toxodontids (Mammalia, Notoungulata) across the Neogene-Quaternary from Argentina |url=https://www.researchgate.net/publication/381031093_Stable_isotope_analysis_evidences_dietary_changes_in_toxodontids_Mammalia_Notoungulata_across_the_Neogene-Quaternary_from_Argentina |journal=Spanish Journal of Palaeontology |doi=10.7203/sjp.28828 |issn=2660-9568 |access-date=15 March 2026 |via=ResearchGate}}</ref>
== 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.<ref name="WelkerCollins2015">{{cite journal|last1=Welker|first1=F.|last2=Collins|first2=M. J.|last3=Thomas|first3=J. A.|last4=Wadsley|first4= M.|last5=Brace|first5 =S.|last6=Cappellini|first6=E.|last7=Turvey|first7=S. T.|last8=Reguero|first8= M.|last9=Gelfo|first9=J. N.|last10=Kramarz|first10= A.|last11=Burger|first11=J.|last12=Thomas-Oates|first12= J.|author12-link=Jane Thomas-Oates|last13= Ashford|first13=D. A.|last14=Ashton|first14=P. D.|last15= Rowsell|first15= K.|last16=Porter|first16=D. M.|last17= Kessler|first17=B.|last18= Fischer|first18=R.|last19=Baessmann|first19= C.|last20=Kaspar|first20=S.|last21=Olsen|first21=J. V.|last22= Kiley|first22=P.|last23=Elliott|first23=J. A.|last24= Kelstrup|first24=C. D.|last25=Mullin|first25= V.|last26= Hofreiter|first26=M.|last27= Willerslev|first27=E.|last28=Hublin|first28=J.-J.|last29=Orlando|first29= L.|last30= Barnes|first30=I.|last31= MacPhee|first31=R. D. E.|author2-link=Matthew Collins (academic)|author17-link=Benedikt Kessler|author27-link=Eske Willerslev|title=Ancient proteins resolve the evolutionary history of Darwin's South American ungulates|journal= Nature|date=18 March 2015|issn=0028-0836|doi= 10.1038/nature14249|volume=522|issue=7554|pages=81–84|pmid=25799987|bibcode=2015Natur.522...81W|s2cid=4467386|url=http://eprints.whiterose.ac.uk/91438/1/Welker_postprint.docx|hdl=11336/14769|hdl-access=free}}</ref><ref name="Buckley2015">{{cite journal|last1= Buckley|first1= M.|title= Ancient collagen reveals evolutionary history of the endemic South American 'ungulates'|journal= Proceedings of the Royal Society B: Biological Sciences|volume= 282|issue= 1806|date= 1 April 2015|article-number= 20142671|doi= 10.1098/rspb.2014.2671|pmid= 25833851|pmc= 4426609}}</ref><ref name="Westbury2017">{{cite journal|last1= Westbury|first1= M.|last2= Baleka|first2= S.|last3= Barlow|first3= A.|last4= Hartmann|first4= S.|last5= Paijmans|first5=J. L. A.|last6= Kramarz|first6= A.|last7= Forasiepi|first7=A. M.|last8= Bond|first8= M.|last9= Gelfo|first9=J. N.|last10= Reguero|first10=M. A.|last11= López-Mendoza|first11= P.|last12= Taglioretti|first12= M.|last13= Scaglia|first13= F.|last14= Rinderknecht|first14= A.|last15= Jones|first15= W.|last16= Mena|first16= F.|last17= Billet|first17= G.|last18=de Muizon|first18= C.|last19= Aguilar|first19=J. L.|last20= MacPhee|first20=R. D. E.|last21= Hofreiter|first21= M.|title=A mitogenomic timetree for Darwin's enigmatic South American mammal ''Macrauchenia patachonica''|journal=Nature Communications|volume= 8|date= 2017-06-27|article-number= 15951|doi= 10.1038/ncomms15951|pmid= 28654082|pmc= 5490259|bibcode= 2017NatCo...815951W}}</ref>
In 2014, a study identifying a new species of toxodontid resolved the families' phylogenetic relations. The below cladogram was found by the study:<ref name="AMFetal2014">{{Cite journal | doi = 10.1007/s12542-014-0233-5| title = New toxodontid (Notoungulata) from the Early Miocene of Mendoza, Argentina| journal = Paläontologische Zeitschrift| volume = 89| issue = 3| pages = 611–634| year = 2014| last1 = Forasiepi | first1 = A. A. M. | last2 = Cerdeño | first2 = E. | last3 = Bond | first3 = M. | last4 = Schmidt | first4 = G. I. | last5 = Naipauer | first5 = M. | last6 = Straehl | first6 = F. R. | last7 = Martinelli | first7 = A. N. G. | last8 = Garrido | first8 = A. C. | last9 = Schmitz | first9 = M. D. | last10 = Crowley | first10 = J. L. | s2cid = 129293436| url = http://sedici.unlp.edu.ar/handle/10915/127531| hdl = 11336/20443 | hdl-access = free }}</ref>
{{clade| style=font-size:85%; line-height:85% |1={{clade |1=''Pampahippus arenalesi'' |2={{clade |1={{clade |1=''Rhynchippus'' spp. |2={{clade |1=''Scarrittia canquelensis'' |2=''Leonitinia gaudri'' }} }} |label2=Toxodontidae |2={{clade |1=''Proadinotherium leptognathum'' |2={{clade |1={{clade |1=''Adinotherium'' spp. |2={{clade |1=''Nesodon taweretus'' |2=''Nesodon imbricatus'' }} }} |2={{clade |1=''Palyeidodon obtusum'' |2={{clade |1=''Hyperoxotodon speciosus'' |2={{clade |1={{clade |1=''Nonotherium henningi'' |2=''Xotodon'' spp. }} |2={{clade |1={{clade |1=''Andinotoxodon bolivariensis'' |2={{clade |1={{clade |1=''Dinotoxodon paranensis'' |2=''Toxodon platensis'' }} |2={{clade |1=''Gyrinodon quassus'' |2={{clade |1=''Ocnerotherium intermedium'' |2=''Hoffstetterius imperator'' }} }} }} }} |2={{clade |1=''Posnanskytherium desaguaderoi'' |2={{clade |1=''Pisanodon nazari'' |2={{clade |1=''Pericotoxodon platignathus'' |2={{clade |1={{clade |1=''Calchaquitherium mixtum'' |2=''Mixotoxodon larensis'' }} |2={{clade |1=''Paratrigodon euguii'' |2=''Trigodon gaudri'' }} }} }} }} }} }} }} }} }} }} }} }} }} }}
== References == {{Reflist}}
== 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}}
== External links == * {{Commons category-inline}} {{Meridiungulata|N.}} {{Taxonbar|from=Q846394}}
Category:Toxodonts Category:Oligocene mammals Category:Miocene mammals of South America Category:Chattian first appearances Category:Holocene extinctions Category:Taxa named by Richard Owen Category:Pliocene notoungulates Category:Prehistoric mammal families