|
Borhyaenid
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 long. ''Borhyaena'' is the type genus of this group. Originally, the borhyaenids were one of the most diverse groups of sparassodonts, including all species not originally included in the Thylacosmilidae. However, in recent years, with the elevation of most sparassodont subfamilies to family rank and the discovery that borhyaenids are more closely related to proborhyaenids and thylacosmilids than other sparassodonts, the family has been reduced to seven species in four genera. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sparassodonts
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 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 Pli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sparassodonta
Sparassodonta (from Ancient Greek, Greek ['], to tear, rend; and , gen. [', '], tooth) is an extinct order (biology), order of carnivore, 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 Phorusrhacidae, terror birds. Previously, it was thought that these mammals died out in the face of competit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 borhyaenids (as Proborhyaeninae). The largest species, ''Proborhyaena gigantea'', is estimated to be about the size of a spectacled bear, with its skull reaching in length, and body mass estimates up to approximately , 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. Most proborhyaenids had a robust, hyena-like skull, although one species, ''Callistoe vincei'', had an elongate, narrow skull more reminiscent of a thylacine. The teeth were strongly specialized as carnassials for eating meat, and in '' Arminiheringia'' rotated throughout the animal's life to maintain a continu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marsupial
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 pouch. Marsupials include opossums, Tasmanian devils, kangaroos, koalas, wombats, wallabies, bandicoots, and the extinct thylacine. Marsupials represent the clade originating from the last common ancestor of extant metatherians, the group containing all mammals more closely related to marsupials than to placentals. They give birth to relatively undeveloped young that often reside in a pouch located on their mothers' abdomen for a certain amount of time. Close to 70% of the 334 extant species occur on the Australian continent (the mainland, Tasmania, New Guinea and nearby islands). The remaining 30% are found in the Americas—primarily in South America, thirteen in Central America, and one species, the Virginia opossum, in North America, n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich from his studies of marine beds in Belgium and Germany. The name comes from the Ancient Greek (''olígos'', "few") and (''kainós'', "new"), and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period. The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. Major changes during the Oligocene included a global expansion o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thylacosmilidae
Thylacosmilidae is an extinct Family (biology), 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''. Taxonomic history The family Thylacosmilidae was originally erected by Riggs in 1933, to accommodate ''Thylacosmilus'', found in the Pliocene Brochero Formation of Argentina. Later, the family was demoted to a subfamily, as Thylacosmilinae, within Borhyaenidae, a group of superficially canid-like sparassodonts, under the assumption that '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene First Appearances
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the Stratum, strata that define the start and en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australohyaena
''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. Description This genus is mainly known from cranial materials, and was related to the genus ''Borhyaena''. Its skull had a short snout, strong and large canines, a particularly deep mandible, and molars with reduced talonids and protocones. It also had a swollen cranial vault, and a well-developed temporal fossa. ''Australohyaena'' was one of the largest predators of its environment, weighing up to .A. M. Forasiepi, M. Judith Babot, and N. Zimicz. 2014. Australohyaena antiqua (Mammalia, Metatheria, Sparassodonta), a large predator from the Late Oligocene of Patagonia. Journal of Systematic Palaeontology 13(6):503-525 DOI: 10.1080/14772019.2014.926403 Classification This genus was until recently only known from isolated teeth, described in 1894 by Florentino Ameghino as ''Borhyaena antiqua'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_(white_background).jpg "Click for more on -> Marsupial")
