Proacrodon

Proacrodon is a dubious genus of extinct mammal from South America. Its type species is Proacrodon transformatus. The only known specimen, a lower premolar or molar, is now lost, and its affinities are unknown.^[1]

In 1899, Santiago Roth named the new genus and species Proacrodon transformatus on the basis of a single tooth collected in Patagonia.^[2] The genus name comes from Greek πρό "before", άκρος "pointed", and όδών "tooth", and refers to the shape of the tooth, which rises higher in its anterior portion than its posterior portion.^[3] Roth compared the taxon to Megacrodon, which he named in the same paper, and to Hyrachyus.^[2] Florentino Ameghino synonymized Proacrodon with his own genus Trimerostephanus without seeing the specimen firsthand.^[1] In 1904, Palmer listed both Proacrodon and Trimerostephanos as members of Isotemnidae.^[4] In 1948 George Gaylord Simpson listed the taxon as a possible litoptern and concluded that the taxon was a nomen vanum, viewing Ameghino's proposal of synonymy with Trimerostephanos as possible but not reliable.^[1]

The locality where the tooth was collected is not known with certainty, but was probably in the Musters Formation.^[1]

References

Works cited

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Genera of South American native ungulates

• Kingdom: Animalia
• Phylum: Chordata
• Class: Mammalia
• Superorder: Laurasiatheria

Xenungulata, Pyrotheria, Astrapotheria, and other minor groups
†Kollpaniidae? Andinodus Molinodus Pucanodus Simoclaenus Tiuclaenus †Didolodontidae Didolodus Enneoconus Ernestokokenia Escribania? Lamegoia Paulogervaisia Raulvaccia Ricardocifellia Saltaodus Umayodus †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
†Litopterna †Protolipternidae Asmithwoodwardia Miguelsoria Protolipterna †Amilnedwardsiidae Amilnedwardsia Ernestohaeckelia Rutimeyeria †Sparnotheriodontidae Notiolofos Phoradiadius Sparnotheriodon Victorlemoinea †Indaleciidae Adiantoides Indalecia †Notonychopidae Notonychops Requisia †Lopholipterna †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 †Proterotheriidae Mesolicaphrium Neodolodus Olisanophus Promylophis Pseudobrachytherium †Anisolambdinae Anisolambda Eolicaphrium Guilielmofloweria Heteroglyphis Lambdaconops Paranisolambda Protheosodon †Proterotheriinae Anisolophus Brachytherium Diadiaphorus Diplasiotherium Eoauchenia Epecuenia Epitherium Lambdaconus Neobrachytherium Neolicaphrium Paramacrauchenia Picturotherium Prolicaphrium Proterotherium Tetramerorhinus Thoatheriopsis Thoatherium Uruguayodon Villarroelia †Megadolodinae Bounodus Megadolodus Uncertain placement Kyraodus Proacrodon Salladolodus Xesmodon Wainka

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