''Proadinotherium'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

toxodontid Toxodontidae is an extinct family of notoungulate mammals, known from the Oligocene to the Holocene (11,000 BP) of South America, with one genus, '' Mixotoxodon'', also known from the Pleistocene of Central America and southwestern North Ame ...

. It lived between the Late

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but ...

and the Early

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

in what is now

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

Description

This genus is only known from very partial remains. From the comparison with its relatives ''

Adinotherium ''Adinotherium'' (meaning "not terrible beast")Palmer (1904) p. 80. is an extinct genus of Toxodontidae, large bodied hoofed ungulates which inhabited South America during the Middle to Late Miocene, from 17.5 to 6.8 Ma and existed for approxi ...

'' and '' Nesodon'', it is supposed that ''Adinotherium'' was an

herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

animal the size of a

sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus ''Ovis'', in everyday usage it almost always refers to domesticated sh ...

, with an elongated body and rather short legs ; it was probably more slender-built than the two latter forms. The legs, in particular, had more delicate and slender bones than those of ''Adinotherium'' and ''Nesodon''. ''Proadinotherium'' was characterized by its teeth with a lower crown, less hypsodont than those of ''Adinotherium'', but evocating more derived toxodontids. Its dentition was complete with a complex structure, and the development of a crest on the molars.

Classification

''Proadinotherium'' is considered to be the most basal and oldest member of the Toxodontidae, the most specialized group of the notoungulates, which included the well known

Pleistocene The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed ...

genus ''

Toxodon ''Toxodon'' (meaning "bow tooth" in reference to the curvature of the teeth) is an extinct genus of South American mammals from the Late Miocene to early Holocene epochs ( Mayoan to Lujanian in the SALMA classification) (about 11.6 million to ...

'', as well as a number of Miocene and

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Florentino Ameghino Florentino Ameghino (born Giovanni Battista Fiorino Giuseppe Ameghino September 19, 1853 – August 6, 1911) was an Argentine naturalist, paleontologist, anthropologist and zoologist, whose fossil discoveries on the Argentine Pampas, especiall ...

, based on fossil remains found in

Argentine Argentines (mistakenly translated Argentineans in the past; in Spanish ( masculine) or ( feminine)) are people identified with the country of Argentina. This connection may be residential, legal, historical or cultural. For most Argentines ...

Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and ...

, with the type species being ''Proadinotherium leptognathum'', known from various remains from the

Santa Cruz Province Santa Claus, also known as Father Christmas, Saint Nicholas, Saint Nick, Kris Kringle, or simply Santa, is a legendary figure originating in Western Christian culture who is said to bring children gifts during the late evening and overnigh ...

and

Chubut Province Chubut ( es, Provincia del Chubut, ; cy, Talaith Chubut) is a province in southern Argentina, situated between the 42nd parallel south (the border with Río Negro Province), the 46th parallel south (bordering Santa Cruz Province), the Andes ran ...

. Ameghino described several other species, from more recent Early Miocene deposits of Patagonia, such as ''P. angustidens'' and ''P. muensteri''. Another species, ''P. saltoni'', was discovered in the Salla Formation in

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

. Other remains attributed to the genus have been found in the

Tremembé Formation Tremembé is a municipality in the state of São Paulo in Brazil. It is part of the Metropolitan Region of Vale do Paraíba e Litoral Norte. The population is 47,714 (2020 est.) in an area of 191.09 km². The elevation is 560 m. A shr ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, the Chaparral Formation of Colombia, and the Agua de la Piedra and

Cerro Bandera Formation The Cerro Bandera Formation is a geological formation in Neuquén Province, Argentina, in northern Patagonia, which dates to the Early Miocene, around 21 to 17.5 million years ago. It predominantly consists of pyroclastic deposits, which were dep ...

s of Mendoza and Neuquén Provinces of Argentina.

References

* *F. Ameghino. 1897. Mammiféres crétacés de l’Argentine (Deuxième contribution à la connaissance de la fauna mammalogique de couches à Pyrotherium). Boletin Instituto Geografico Argentino 18(4–9):406-521 *F. Ameghino. 1902. Première contribution à la connaissance de la fauna mammalogique des couches à Colpodon. Boletin de la Academia Nacional de Ciencias de Córdoba 17:71-141 Toxodonts Prehistoric placental genera Oligocene mammals of South America Miocene mammals of South America Paleogene Argentina Neogene Argentina Fossils of Argentina Neogene Colombia Fossils of Colombia Paleogene Bolivia Fossils of Bolivia Paleogene Brazil Fossils of Brazil Colhuehuapian Deseadan Fossil taxa described in 1894 Taxa named by Florentino Ameghino Golfo San Jorge Basin Neuquén Basin Sarmiento Formation Cerro Bandera Formation {{paleo-mammal-stub