| Proborhyaena | |
|---|---|
 | |
| Skull of Proborhyaena gigantea | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | † Sparassodonta |
| Family: | † Proborhyaenidae |
| Genus: | † Proborhyaena Ameghino, 1897 |
| Species: | †P. gigantea |
| Binomial name | |
| †Proborhyaena gigantea Ameghino, 1897 | |
Proborhyaena is an extinct genus of proborhyaenid sparassodont that lived during the Oligocene of what is now South America. It is considered to be the largest of the sparassodonts.
Proborhyaena was very large in size, with the skull alone reaching up to 60 cm (2.0 ft), [1] and the whole animal may have been as large as a present-day spectacled bear. [2] Sorkin (2008) speculated that that Proborhyaena gigantea may have weighed up to 600 kg (1,300 lb), [3] but subsequent studies consider this an overestimate and argue that it would have weighed up to 90–200 kg (200–440 lb). [4] [2] [5]
Proborhyaena was a massive animal, with a robust and powerful body. Its skull was equipped with a short, high snout, and its caniniform teeth were saber-shaped, although not as developed as those of the later Thylacosmilus . The canines, in contrast to those of Thylacosmilus 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. [6]
Proborhyaena was first described by Florentino Ameghino in 1897, based on fossils found in Patagonia in deposits dating to the Late Oligocene (Deseadan). Subsequently, more fossils ascribed to this species were found from the Salla Formation of Bolivia, [7] and the Fray Bentos Formation of Uruguay, [8] which suggests a wide distribution and success of this sparassodont. [9] In addition, fossils assigned to Proborhyaena have been found in the Agua de la Piedra Formation of Mendoza Province, Argentina. [10]
Proborhyaena is the eponymous genus of the family Proborhyaenidae, also including smaller forms such as Callistoe and Arminiheringia these animals belonged to the sparassodonts, a group of metatherian mammals akin to marsupials that in South America occupied the ecological niches typical of other carnivorous mammal groups on other continents. Proborhyaena may be the largest carnivorous metatherians that ever lived.
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 . Both Proborhyaena and numerous large ungulates became extinct during the Oligocene, and it is likely that this predator-prey ratio was influenced by climate change. [11]
Opossums are members of the marsupial order Didelphimorphia endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 126 species in 18 genera. Opossums originated in South America and entered North America in the Great American Interchange following the connection of North and South America.
Paucituberculata is an order of South American marsupials. Although currently represented only by the seven living species of shrew opossums, this order was formerly much more diverse, with more than 60 extinct species named from the fossil record, particularly from the late Oligocene to early Miocene epochs. The earliest paucituberculatans date to the late Paleocene. The group went through a pronounced decline in the middle Miocene epoch, which resulted in the extinction of all families of this order except for the living shrew opossums (Caenolestidae). Extinct families of Paucituberculatans include Pichipilidae, Palaeothentidae, and Abderitidae.
Sparassodonta 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 thought to be a separate side branch that split before the last common ancestor of all modern marsupials. A number of these mammalian predators closely resemble placental predators that evolved separately on other continents, and are cited frequently as examples of convergent evolution. They were first described by Florentino Ameghino, from fossils found in the Santa Cruz beds of Patagonia. Sparassodonts were present throughout South America's long period of "splendid isolation" during the Cenozoic; during this time, they shared the niches for large warm-blooded predators with the flightless terror birds. Previously, it was thought that these mammals died out in the face of competition from "more competitive" placental carnivorans during the Pliocene Great American Interchange, but more recent research has showed that sparassodonts died out long before eutherian carnivores arrived in South America. Sparassodonts have been referred to as borhyaenoids by some authors, but currently the term Borhyaenoidea refers to a restricted subgroup of sparassodonts comprising borhyaenids and their close relatives.
Thylacosmilus is an extinct genus of saber-toothed metatherian mammals that inhabited South America from the Late Miocene to Pliocene epochs. Though Thylacosmilus looks similar to the "saber-toothed cats", it was not a felid, like the well-known North American Smilodon, but a sparassodont, a group closely related to marsupials, and only superficially resembled other saber-toothed mammals due to convergent evolution. A 2005 study found that the bite forces of Thylacosmilus and Smilodon were low, which indicates the killing-techniques of saber-toothed animals differed from those of extant species. Remains of Thylacosmilus have been found primarily in Catamarca, Entre Ríos, and La Pampa Provinces in northern Argentina.
Megistotherium is an extinct genus of hyaenodont belonging to the family Hyainailouridae that lived in Africa.
Pyrotherium 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. It was named Pyrotherium because the first specimens were excavated from an ancient volcanic ash deposit. Fossils of the genus have been found in the Deseado and Sarmiento Formations of Argentina and the Salla Formation of Bolivia.
Borhyaenidae is an extinct metatherian family of low-slung, heavily built predatory mammals in the order Sparassodonta. Borhyaenids are not true marsupials, but members of a sister taxon, Sparassodonta. Like most metatherians, borhyaenids and other sparassodonts are thought to have had a pouch to carry their offspring around. Borhyaenids had strong and powerful jaws, like those of the unrelated placentalians Hyaenodon and Andrewsarchus, for crushing bones. Borhyaenids grew up to an average of 5 to 6 feet long.
Cramauchenia is an extinct genus of litoptern South American ungulate. Cramauchenia was named by Florentino Ameghino. The name has no literal translation. Instead, it is an anagram of the name of a related genus Macrauchenia. This genus was initially discovered in the Sarmiento Formation in the Chubut Province, in Argentina, and later it was found in the Chichinales Formation in the Río Negro Province and the Cerro Bandera Formation in Neuquén, also in Argentina, in sediments assigned to the SALMA Colhuehuapian, as well as the Agua de la Piedra Formation in Mendoza, in sediments dated to the Deseadan. In 1981 Soria made C. insolita a junior synonym of C. normalis. A specimen of C. normalis was described in 2010 from Cabeza Blanca in the Sarmiento Formation, in sediments assigned to the Deseadan SALMA.
Anachlysictis gracilis is an extinct carnivorous mammal belonging to the group Sparassodonta, which were metatherians that inhabited South America during the Cenozoic. Anachlysictis is the first record of such borhyaenoids in northern South America, and also the most primitive known member of the family Thylacosmilidae, a group of predators equipped with "saber teeth". It was also the only confirmed record of a thylacosmilid that did not belong to the genus Thylacosmilus until the official publication of Patagosmilus in 2010.
Dukecynus is an extinct genus of meat-eating metatherian belonging to the order Sparassodonta, which lived in South America during the Middle Miocene (Laventan), between about 13.8 and 11.8 million years ago. The name of the genus meaning "Duke dog", for Duke University and the Greek word cynos, dog, for the pretended similarity of this animal with dogs. A single species known so far, Dukecynus magnus. The species name "magnus" derives from Latin for big, to reflect their great size.
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 borhyaenids. The largest species, Proborhyaena gigantea, is estimated to be about the size of a spectacled bear, with its skull reaching 60 cm (2.0 ft) in length, and body mass estimates up to approximately 90–200 kg (200–440 lb), making the proborhyaenids some of the largest known metatherians. Proborhyaenid remains have been found in western Bolivia, Uruguay, southern Brazil, and the provinces of Mendoza, Salta, and Chubut, in Argentina.
Thylacosmilidae is an extinct family of metatherian predators, related to the modern marsupials, which lived in South America between the Miocene and Pliocene epochs. Like other South American mammalian predators that lived prior to the Great American Biotic Interchange, these animals belonged to the order Sparassodonta, which occupied the ecological niche of many eutherian mammals of the order Carnivora from other continents. The family's most notable feature are the elongated, laterally flattened fangs, which is a remarkable evolutionary convergence with other saber-toothed mammals like Barbourofelis and Smilodon.
Pharsophorus is an extinct genus of borhyaenoid sparassodont that inhabited South America during the Middle to Late Oligocene epoch.
Thylophorops is an extinct genus of didelphine opossums from the Pliocene of South America. Compared to their close didelphine cousins like the living Philander and Didelphis opossums, Thylophorops displays specialization towards carnivory, and one species, T. lorenzinii, is the largest known opossum of all time, which could imply a macropredatory role.
The Agua de la Piedra Formation is a Late Oligocene geologic formation of the Malargüe Group that crops out in the southernmost Precordillera and northernmost Neuquén Basin in southern Mendoza Province, Argentina.
Ronwolffia is an extinct genus of horned armadillo (Peltephilidae), distantly related to the modern species of armadillos and to the extinct glyptodonts. It lived during the Oligocene in what is now the Salla Formation in Bolivia.
Fiandraia is an extinct monotypic genus of notoungulate that lived in Uruguay during the Oligocene and the Early Miocene. It was found in the Fray Bentos Formation, in rocks dated back from the Deseadan period.
Australohyaena is an extinct genus of carnivorous mammal, belonging to the order Sparassodonta. It lived during the Late Oligocene, and its fossilized remains were discovered in Argentina.
The Sarmiento Formation, in older literature described as the Casamayor Formation, is a geological formation in Chubut Province, Argentina, in central Patagonia, which spans around 30 million years from the mid-Eocene to the early Miocene. It predominantly consists of pyroclastic deposits, which were deposited in a semi-arid environment. It is divided up into a number of members. The diverse fauna of the Sarmiento Formation, including a variety of birds, crocodilians, turtles and snakes, also includes many mammals such as South American native ungulates as well as armadillos, and caviomorph rodents.
The Fray Bentos Formation is a Deseadan geologic formation of the Paysandú Group in Uruguay and portions of Argentina, corresponding to the Paraná Basin. It is composed of calcareous sandstones and siltstones with a pinkish-orange coloration. It outcrops in southwestern Uruguay, the central and southeastern part of the province of Corrientes and northeast Entre Ríos.
