''Eurygenium'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

notoungulate Notoungulata is an extinct order of mammalian ungulates that inhabited South America from the early Paleocene to the Holocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms resemb ...

belonging to the family

Notohippidae Notohippidae is a paraphyly, paraphyletic extinct Family (biology), family of Notoungulata, notoungulate mammals from South America. Notohippids are known from the Eocene and Oligocene Epoch (reference date), epochs.McKenna, Malcolm C., and Bell ...

. It lived during 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 the ...

in what is today

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 southe ...

Description

It was a medium-sized mammal ; the best known species, ''Eurygenium pacegnum'', was approximately 80 centimeters long and weighed 10 kilograms. Its body was relatively compact, with more robust legs than its relatives, such as ''

Rhynchippus ''Rhynchippus'' ("Snout Horse") is an extinct genus of notoungulate mammals from the Late Oligocene ( Deseadan in the SALMA classification) of South America. The genus was first described by Florentino Ameghino in 1897 and the type species is ' ...

''; unlike the latter, however, ''Eurygenium'' had tetradactyls forelegs and a third

trochanter A trochanter is a tubercle of the femur near its joint with the hip bone. In humans and most mammals, the trochanters serve as important muscle attachment sites. Humans are known to have three trochanters, though the anatomic "normal" includes ...

near the femoral midline. The skull of ''Eurygenium'' was characterized by a short and broad muzzle, with strong and laterally expanded zygomatic arches. The dentition was devoid of diastema. As in all

, premolars and molars had a very high crown (hypsodont). The upper premolars lacked an anterolingual cingulum, while the posterolingual cingulum was reduced. The lower incisors cingulum was reduced or absent, while the lower premolars and molars had a dimple at the trigonid-talonid edge, but there was no dimple in the entolophid.

Classification

''Eurygenium'' was a member of

, a possibly paraphiletic family of toxodont notoungulates. ''Eurygenium'' was a basal representative of a derived group of Notohippids, comprising numerous forms such as ''

Argyrohippus ''Argyrohippus'' is an extinct genus of notoungulate, belonging to the family Notohippidae. It lived from the Late Oligocene to the Early Miocene, and its fossilized remains were found in South America. Description This animal was probably v ...

'' and ''

''. ''Eurygenium'' was first described in 1895 by

Florentino 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, especially ...

, based on fossilized remains found in terrains dated from the Late

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, s ...

Patagonia. The type species is ''Eurygenium latirostris'', but Ameghino described himself the species ''E. normalis'', from the Late Oligocene of Patagonia. ''E. pacegnum'' was described in 1997, based on relatively well preserved specimens found in the

Salla Formation Salla (''Kuolajärvi'' until 1936) ( smn, Kyelijävri) is a municipality of Finland, located in Lapland. The municipality has a population of () and covers an area of of which is water. The population density is . The nearby settlement of Sa ...

, 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 ...

Bibliography

*F. Ameghino. 1895. Première contribution à la connaissance de la faune mammalogique des couch à Pyrotherium. Boletín Instituto Geográfico Argentino 15: 603–660. *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 *B. J. Shockey. 1997. Two new notoungulates (Family Notohippidae) from the Salla Beds of Bolivia (Deseadan: Late Oligocene): systematics and functional morphology. Journal of Vertebrate Paleontology 17(3):584-599 *H. Marani and M. T. Dozo. 2008. El cráneo más completo de Eurygenium latirostris Ameghino, 1895 (Mammalia, Notoungulata), un Notohippidae del Deseadense (Oligoceno Tardío) de la Patagonia, Argentina. Ameghiniana 45(3):619-626 {{Taxonbar, from=Q110456216 Toxodonts Oligocene mammals of South America Paleogene Argentina Fossils of Argentina Paleogene Bolivia Fossils of Bolivia Fossil taxa described in 1895 Taxa named by Florentino Ameghino Prehistoric placental genera Golfo San Jorge Basin Sarmiento Formation