''Proborhyaena'' is an extinct genus of proborhyaenid

sparassodont Sparassodonta (from Greek to tear, rend; and , gen. , ' tooth) is an extinct order of carnivorous metatherian mammals native to South America, related to modern marsupials. They were once considered to be true marsupials, but are now thoug ...

that lived during the

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 ...

of 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 southe ...

. It is considered to be the largest of the sparassodonts.

Description

This animal was very large in size, with the skull alone reaching up to 40 centimeters long, and the whole animal may have been as large as a present-day

grizzly bear The grizzly bear (''Ursus arctos horribilis''), also known as the North American brown bear or simply grizzly, is a population or subspecies of the brown bear inhabiting North America. In addition to the mainland grizzly (''Ursus arctos horri ...

. It is speculated that ''Proborhyaena'' may have weighed up to . It was a massive animal, with a robust and powerful body. Its skull was equipped with a short, high snout, and its

caniniform In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened howeve ...

teeth were saber-shaped, although not as developed as those of the later ''

Thylacosmilus ''Thylacosmilus'' is an extinct genus of Saber-toothed predator, saber-toothed metatherian mammals that inhabited South America from the Miocene, Late Miocene to Pliocene Epoch (geology), epochs. Though ''Thylacosmilus'' looks similar to the "Mac ...

''. The canines, in contrast to those of ''

'' which had an "almond-shaped" section and a sharp margin, were ovoid in cross-section and thus must have been much more robust. Like the thylacosmilids, ''Proborhyaena'' possessed only one pair of lower

incisors Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wh ...

Classification

''Proborhyaena'' was first described 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 ...

1897 Events January–March * January 2 – The International Alpha Omicron Pi sorority is founded, in New York City. * January 4 – A British force is ambushed by Chief Ologbosere, son-in-law of the ruler. This leads to a puniti ...

, based on fossils found in

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 gl ...

in deposits dating to the Late

(Deseadan). Subsequently, more fossils ascribed to this species were found from 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 ...

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 ...

, and the

Fray Bentos Formation Fray or Frays or The Fray may refer to: Arts, entertainment, and media Fictional entities *Fray, a phenomenon in Terry Pratchett's ''The Carpet People'' *Fray, the main character in the video games: **''Fray in Magical Adventure'' **''Fray CD'' ...

Uruguay Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...

, which suggests a wide distribution and success of this sparassodont. In addition, fossils assigned to ''Proborhyaena'' have been found in the

Agua de la Piedra Formation The Agua de la Piedra Formation (FAP, Spanish names include ''Estratos de Agua de la Piedra'' and ''Complejo Volcano-sedimentario del Terciario inferior'')Combina et al., 1994, p.418 is a Late Oligocene (Deseadan in the SALMA classification) geol ...

Mendoza Province Mendoza, officially Province of Mendoza, is a province of Argentina, in the western central part of the country in the Cuyo region. It borders San Juan to the north, La Pampa and Neuquén to the south, San Luis to the east, and the republic o ...

, Argentina. ''Proborhyaena'' is the eponymous genus of the family

Proborhyaenidae Proborhyaenidae is an extinct family of metatherian mammals of the order Sparassodonta, which lived in South America from the Eocene (Mustersan) until the Oligocene (Deseadan). Sometimes it has been included as a subfamily of their relatives, the ...

, also including smaller forms such as ''

Callistoe ''Callistoe'' is an extinct genus of sparassodont. It lived during the Early Eocene, and its fossilized remains were found in South America. Description Unlike most of its relatives, such as '' Proborhyaena'' and ''Arminiheringia'', ''Callistoe ...

'' and ''

Arminiheringia ''Arminiheringia'' is an extinct genus of sparassodont. It lived during the Early Eocene in South America. Description This animal had an exceptionally robust skull with strong teeth. The lower canines were exceptionally long and projected forw ...

'' these animals belonged to the sparassodonts, a group of metatherian mammals akin to

marsupials Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a po ...

that in South America occupied the

ecological niches In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of resources and competitors (for ...

typical of other

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...

mammal groups on other continents. ''Proborhyaena'' may be the largest carnivorous metatherians that ever lived.

Paleobiology

This animal must have been a fearsome marauder that certainly did not chase prey for long; it probably fed on large, slow-moving prey, such as ''

Pyrotherium ''Pyrotherium'' ('fire beast') is an extinct genus of South American ungulate, of the order Pyrotheria, that lived in what is now Argentina and Bolivia, during the Late Oligocene.ungulates Ungulates ( ) are members of the diverse clade Ungulata which primarily consists of large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses, and tapirs; and even-toed ungulates such as cattle, pigs, giraffes, cam ...

became extinct during the Oligocene, and it is likely that this predator-prey ratio was influenced by climate change.

References

{{Taxonbar, from=Q21227684 Sparassodonts Oligocene mammals of South America Prehistoric mammal genera Paleogene Argentina Fossils of Argentina Paleogene Bolivia Fossils of Bolivia Paleogene Uruguay Fossils of Uruguay Deseadan Fossil taxa described in 1897 Taxa named by Florentino Ameghino Golfo San Jorge Basin Sarmiento Formation