Ethegotherium

Ethegotherium Temporal range: Middle-Late Miocene ~18–14 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	†Notoungulata
Family:	†Hegetotheriidae
Genus:	†Ethegotherium Minoprio, 1947
Species:	†E. carettei
Binomial name
†Ethegotherium carettei Minoprio, 1947

Ethegotherium is an extinct genus of Notoungulates, belonging to the suborder Typotheria. It lived from the Lower to the Middle Miocene, and its fossilized remains were discovered in South America. It might be a synonym of the genus Prohegetotherium.

Description

This was a small-sized animal, not exceeding the size of a European rabbit. Ethegotherium is only known from a skull and a mandible, and it is difficult to restore its complete appearance. From comparison with its relatives, it can be supposed that it was a small notoungulate with a short tail and long hind legs. It shared similarities with the slightly older Prohegetotherium, but differed from it in several ways, including its smaller size.

The incisors and canines were directed forward, giving rise to a "false diastema" between them and the backward-directed first premolars. The upper canine had an arched crown, while the upper jugal teeth, with a high crown, were slightly imbricated, without any development of the parastyle area and with discontinuous enamel. Unlike Prohegetotherium, the first upper premolar had no labial sulcus nor parastyle, while the second premolar had a deep lingual sulcus and the third premolar was quite large. For the lower molars, the trigonid was rounded and not cordiform like in Prohegetotherium.

Classification

Ethegotherium was a member of the Hegetotheriidae, a group of small-sized Notoungulates, similar in appearance to lagomorphs. The dental characteristics of this animal indicates affinities with Prohegetotherium and Hegetotherium, within the Hegetotheriinae subfamily.

The holotype of Ethegotherium carettei was first described in 1947 by José Luis Minoprio, based on fossils found in the Mendoza Province of Argentina, and firstly attributed to the genus Prohegetotherium as P. carettei. Later, a study by George Gaylord Simpson, Bryan Patterson and Minoprio himself identified several sufficiently distinctive characteristics for the establishment of a new genus, Ethegotherium (whose name is the anagram of Hegetotherium). However, there is still some debate on the exact generic attribution of the fossils.^[1] It was initially thought to have come from the Divisadero Largo Formation of the Late Eocene, but further analyses of the rock matrix of the fossil tends to indicate that the holotype came from the Miocene Mariño Formation.^[2]

References and Bibliography

• Minoprio, J. L. (1947): Fósiles de la Formación Divisadero Largo. – Anales Sociedad Científica Argentina, 144: 365–378.
• Simpson, G. G., Minoprio, J. L. & Patterson, B. (1962): The mammalian fauna of the Divisadero Largo Formation. Mendoza, Argentina. – Bulletin of the Museum of Comparative Zoology, 127: 239–293.
• Lopez, G. M. (2002): Redescripción de Ethegotherium carettei (Notoungulata, Hegetotheriidae) de la Formación Divisadero Largo de la provincia de Mendoza, Argentina. – Ameghiniana, 39 (3): 295–306.

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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