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Xenungulata Temporal range: Late Paleocene-Early Eocene (Riochican-Casamayoran) ~58.6–48.7 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Interpretation of Carodnia vieirai
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Infraclass:	Placentalia
Clade:	†Meridiungulata
Order:	†Xenungulata Paula Couto 1952
Family and genera
†Carodniidae Paula Couto 1952 †Carodnia Simpson 1935 †Etayoa Villarroel 1987 †Rodcania Gelfo, García-López & Bergqvist 2020 †Notoetayoa Gelfo, López & Bond 2008

Xenungulata ("strange ungulates") is an order of extinct and primitive South American hoofed mammals that lived from the Late Paleocene to Early Eocene (Itaboraian to Casamayoran in the SALMA classification). Fossils of the order are known from deposits in Brazil, Argentina, Peru, and Colombia. The best known member of this enigmatic order is the genus Carodnia, a tapir-like and -sized animal with a gait similar to living African elephants.

Description

Xenungulates are characterized by bilophodont M and M_1–2, similar to pyrotheres, and complex lophate third molars, similar to uintatheres. Though other relationships, to arctocyonids for example, have been suggested, no proofs thereof have been found. The foot bones of xenungulates were short and robust and their digits terminated in broad, flat, and unfissured hoof-like unguals, quite unlike any other meridiungulates. The discovery of Etayoa in Colombia made it clear that xenungulates are distinct from other groups: Etayoa lacks lophate molar talonid (in contrast to Carodnia) and, since no distinct lophodonty is present in basal pyrotheres, there is reason to assume that bilophodonty evolved separately in xenungulates and pyrotheres. Xenungulates also show some dental similarity to primitive astrapotheres.

Taxonomy

Cifelli 1983 grouped Carodnia with pyrotheres based on a similarity in astragalus morphology, but later concluded that this observation was incorrect.

Notoetayoa is most closely related to Etayoa.

Distribution

Xenungulata fossils have been found in:

• Bogotá Formation, Casamayoran, Colombia
• Peñas Coloradas Formation, Riochican, Argentina
• Mogollón Formation, Itaboraian-Riochican, Peru
• Itaboraí Formation, Itaboraian, Brazil

References

1. Carodniidae in the Paleobiology Database. Retrieved May 2013.
2. Gelfo, Javier N.; García-López, Daniel A.; Bergqvist, Lilian P. (2020). "Phylogenetic relationships and palaeobiology of a new xenungulate (Mammalia: Eutheria) from the Palaeogene of Argentina". Journal of Systematic Palaeontology. 18 (12): 993–1007. doi:10.1080/14772019.2020.1715496. S2CID 213052956.
3. "Xenungulata". Palaeocritti. Retrieved 4 May 2013.
4. Antoine et al. 2015
5. Fariña, Vizcaíno & De Iuliis 2013, p. 86
6. Villarroel 1987
7. Rose 2006, Xenungulata, p. 238
8. Gingerich 1985, p. 131
9. Gelfo, López & Bond 2008, Abstract
10. Xenungulata at Fossilworks.org

Bibliography

• Antoine, Pierre-Olivier; Billet, Guillaume; Salas Gismondi, Rodolfo; Tejada Lara, Julia; Baby, Patrice; Brusset, Stéphane; Espurt, Nicolas (2015). "A New Carodnia Simpson, 1935 (Mammalia, Xenungulata) from the Early Eocene of Northwestern Peru and a Phylogeny of Xenungulates at Species Level". Journal of Mammalian Evolution. 22 (2): 129–140. Retrieved 2019-02-13.
• Cifelli, Richard (1983). "Eutherian tarsals from the late Paleocene of Brazil". American Museum Novitates (2761). hdl:2246/5252. OCLC 10601277.Cifelli 1983
• Fariña, Richard A.; Vizcaíno, Sergio F.; De Iuliis, Gerry (2013). Megafauna: Giant Beasts of Pleistocene South America. Indiana University Press. ISBN 9780253007193. OCLC 779244424. Retrieved 4 May 2013.Fariña, Vizcaíno & De Iuliis 2013
• Gelfo, Javier N.; López, Guillermo M.; Bond, Mariano (2008). "A new Xenungulata (Mammalia) from the Paleocene of Patagonia Argentina". Journal of Paleontology. 82 (2): 329–35. doi:10.1666/06-099.1. OCLC 4631927277. S2CID 131263926.Gelfo, López & Bond 2008
• Gingerich, Philip D. (1985). "South American Mammals in the Paleocene of North America" (PDF). In Stehli, Francis G.; Webb, S. David (eds.). The Great American Biotic Interchange. Topics in Geobiology. Vol. 4. Springer. pp. 123–137. doi:10.1007/978-1-4684-9181-4_5. ISBN 978-1-4684-9183-8. OCLC 716806225. Retrieved 4 May 2013.Gingerich 1985
• Rose, Kenneth David (2006). The beginning of the age of mammals. Baltimore: JHU Press. ISBN 978-0801884726.Rose 2006
• Paula Couto, Carlos, de (1952). "Fossil mammals from the beginning of the Cenozoic in Brazil. Condylarthra, Litopterna, Xenungulata, and Astrapotheria". Bulletin of the American Museum of Natural History. 99: 355–394. hdl:2246/417. OCLC 18189741.{{cite journal}}: CS1 maint: multiple names: authors list (link)Paula Couto 1952
• Simpson, George Gaylord (1935). "Descriptions of the oldest known South American mammals, from the Río Chico Formation". American Museum Novitates. Publications of the Scarritt Expeditions, no. 24 (793). hdl:2246/2125. OCLC 44083494.Simpson 1935
• Villarroel, Carlos (1987). "Características y afinidades de Etayoa n. gen., tipo de una nueva familia de Xenungulata (Mammalia) del Paleoceno medio (¿) de Colombia". Comunicaciones Paleontologicas del Museo de Historia Natural del Montevideo. 1 (19): 241–253. OCLC 18731966.Villarroel 1987

v t e Genera of South American native ungulates
Kingdom: Animalia Phylum: Chordata Class: Mammalia Superorder: Laurasiatheria
Xenungulata, Pyrotheria, Astrapotheria, and other minor groups †Kollpaniidae? Andinodus Molinodus Pascualodus? Pucanodus Simoclaenus Tiuclaenus †Didolodontidae Didolodus Enneoconus Ernestokokenia Escribania? Lamegoia Paulogervaisia Raulvaccia Ricardocifellia Saltaodus Umayodus Xesmodon †Protolipternidae Asmithwoodwardia Miguelsoria Protolipterna †Xenungulata †Carodniidae Carodnia Etayoa Notoetayoa Rodcania †Pyrotheria †Colombitheriidae Colombitherium Proticia †Pyrotheriidae Baguatherium Berracotherium Carolozittelia Griphodon Propyrotherium Pyrotherium †Astrapotheria Eoastrapostylops †Trigonostylopidae Shecenia Tetragonostylops Trigonostylops †Astrapotheriidae Antarctodon Astrapodon Comahuetherium Liarthrus Maddenia Parastrapotherium †Albertogaudryinae Albertogaudrya Astraponotus †Astrapotheriinae Astrapothericulus Astrapotherium Scaglia †Uruguaytheriinae Granastrapotherium Hilarcotherium Uruguaytherium Xenastrapotherium
Litopterna †Eulitopterna †Adianthidae Adianthus Proadiantus Proectocion? Proheptaconus Thadanius Tricoelodus †Macraucheniidae Polymorphis †Cramaucheniinae Caliphrium Coniopternium Cramauchenia Llullataruca Phoenixauchenia Pternoconius Theosodon †Macraucheniinae Cullinia Huayqueriana Macrauchenia Macraucheniopsis Micrauchenia Oxyodontherium Paranauchenia Promacrauchenia Scalabrinitherium Windhausenia Xenorhinotherium †Proterotherioidea †Anisolambdidae †Anisolambdinae Anisolambda Eolicaphrium Guilielmofloweria Lambdaconops Paranisolambda Polyacrodon Protheosodon Wainka †Sparnotheriodontinae Heteroglyphis Notiolofos Phoradiadius Sparnotheriodon Victorlemoinea †Proterotheriidae Mesolicaphrium Neodolodus Olisanophus Promylophis Prothoatherium Pseudobrachytherium Salladolodus †Megadolodinae Bounodus Megadolodus †Proterotheriinae Anisolophus Brachytherium Diadiaphorus Diplasiotherium Eoauchenia Epecuenia Epitherium Lambdaconus Neobrachytherium Neolicaphrium Paramacrauchenia Picturotherium Prolicaphrium Proterotherium Tetramerorhinus Thoatheriopsis Thoatherium Uruguayodon Villarroelia †Notopterna †Amilnedwardsiidae Amilnedwardsia Ernestohaeckelia Rutimeyeria †Indaleciidae Adiantoides Indalecia †Notonychopidae Notonychops Requisia Incertae sedis Kyraodus Proacrodon
Notoungulata incertae sedis Acoelodus Archaeogaia Carolodarwinia Perutherium †Notioprogonia Satshatemnus Seudenius †Henricosborniidae Henricosbornia Nanolophodon Othnielmarshia Peripantostylops Simpsonotus †Notostylopidae Boreastylops Chilestylops Edvardotrouessartia Homalostylops Notostylops Otrhonia Parastylops †Toxodontia †Homalodotheriidae Asmodeus Chasicotherium Homalodotherium Trigonolophodon †Isotemnidae Anisotemnus Coelostylodon Distylophorus Hedralophus Isotemnus Lophocoelus Pampatemnus Periphragnis Pleurocoelodon Pleurostylodon Rhyphodon Thomashuxleya †Eutoxodontia †Leontiniidae Anayatherium Ancylocoelus Colpodon Coquenia Elmerriggsia Gualta Henricofilholia Huilatherium Leontinia Martinmiguelia Purperia? Scarrittia Taubatherium Termastherium †Notohippidae Acoelohyrax Argyrohippus Deuterotherium? Edvardocopeia Eomorphippus Eurygenium Mendozahippus Moqueguahippus Morphippus Nesohippus Notohippus Pampahippus Pascualihippus Patagonhippus Perhippidion Plexotemnus Puelia Purperia? Rhynchippus Rosendo Stilhippus Teushentherium Trimerostephanos †Toxodontidae †Nesodontinae Adinotherium Nesodon Proadinotherium †Toxodontinae Abothrodon Andinotoxodon Calchaquitherium Ceratoxodon Charruatoxodon Dinotoxodon Eutomodus Falcontoxodon Gyrinodon Haplodontherium Hemixotodon Hoffstetterius Hyperoxotodon Mesenodon Mesotoxodon Minitoxodon Mixotoxodon Neoadinotherium Neotoxodon Nesodonopsis Nonotherium Ocnerotherium Palyeidodon Paratrigodon Pericotoxodon Piauhytherium Pisanodon Plesiotoxodon Posnanskytherium Prototrigodon Stenotephanos Stereotoxodon Toxodon Toxodontherium Trigodon Trigodonops Xotodon †Typotheria Campanorco Griphotherion †Archaeopithecidae Archaeopithecus Teratopithecus †Oldfieldthomasiidae Allalmeia Brachystephanus Camargomendesia Colbertia Dolichostylodon Itaboraitherium Kibenikhoria Maxschlosseria Oldfieldthomasia Paginula Suniodon Tsamnichoria Ultrapithecus Xenostephanus †Interatheriidae Antofagastia Ignigena Johnbell Munizia Punapithecus †Interatheriinae Archaeophylus Argyrohyrax Boleatherium Brucemacfaddenia Caenophilus Choichephilum Cochilius Eopachyrucos Federicoanaya Interatherium Juchuysillu Miocochilius Neoicochilus Patriarchus Proargyrohyrax Progaleopithecus Protypotherium Santiagorothia †Notopithecinae Antepithecus Guilielmoscottia Notopithecus Transpithecus †Mesotheriidae Fiandraia? Trachytherus †Mesotheriinae Altitypotherium Caraguatypotherium Eotypotherium Eutypotherium Hypsitherium Mesotherium Microtypotherium Plesiotypotherium Pseudotypotherium Rusconitherium Typotheriopsis †Archaeohyracidae Archaeohyrax Archaeotypotherium Bryanpattersonia Eohyrax Pascualhyrax Protarchaeohyrax Pseudhyrax Punahyrax †Hegetotheriidae †Hegetotheriinae Ethegotherium Hegetotheriopsis Hegetotherium Hemihegetotherium Prohegetotherium Pseudohegetotherium Sallatherium †Pachyrukhinae Medistylus Propachyrucos Prosotherium Tremacyllus †Pachyrukhini Pachyrukhos Paedotherium Tremacyllus

• Xenungulata
• Meridiungulata
• Paleocene first appearances
• Eocene extinctions
• Taxa described in 1952
• Mammal orders
• Prehistoric tetrapod orders