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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'' had a narrow, puny snout, and the shape of its skull resembled that of a thylacine. ''Callistoe'' lacked the characteristics associated with the ability to climb in its limbs and vertebrae. The shape of its limb joints, the presence of an ossified patella and the shape of the limb bones show that it was limited to a parasagittal gait, and possessed little flexibility in its elbows, wrists, knees and ankles ; ''Callistoe'' probably specialized in walking and running. ''Callistoe'', approximately two meters long, had a slender and light body, and weighed approximately 23 kilograms. Classification ''Callistoe vincei'' was first described in 2002, based on an almost complete and exceptionally preserved skeleton from the Lumbrera Formation ... [...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] |
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 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] |
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 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] |
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] |
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 forward. The molars and premolars suggests a carnivorous diet. Its body was probably massive, and the animal reached a considerable size, about 1.8 meters in length. Its legs were strong and sturdy, with a general appearance probably resembling that of a modern bear. Classification ''Arminiheringia'' was a typical member of the family Proborhyaenidae, a clade of South American bear-like metatherians. Those animals belonged to the order Sparassodonta, a clade related to marsupials whose members, during the course of their evolution, occupied niches ordinarily occupied on other continents by carnivores. Arminiheringia and its relatives superficially resembled creodont Creodonta ("meat teeth") is a former order of extinct carnivorous placent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proborhyaena
''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. 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. 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 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. Classification ''Proborhyaena'' was first described by Florentino Ameghino in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), 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 Carbon-13, 13C in the atmosphere was exceptionally low in comparison with the more common isotope Carbon-12, 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 Popigai impact structure, Siberia and in what is now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleogene Argentina
The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning of the Neogene Period Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon. The earlier term Tertiary Period was used to define the span of time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognised as a formal stratigraphic term, 'Tertiary' is still widely found in earth science literature and remains in informal use. Paleogene is often abbreviated "Pg" (but the United States Geological Survey uses the abbreviation PE for the Paleogene on the Survey's geologic maps). During the Paleogene, mammals diversified from relatively small, simple forms into a large group of diverse animals in the wake of the Cretaceous–Paleogene extinction event that ended the preceding Cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossils Of Argentina
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene Mammals Of South America
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 strata that define the start and end of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mustelidae
The Mustelidae (; from Latin ''mustela'', weasel) are a family of carnivorous mammals, including weasels, badgers, otters, ferrets, martens, minks and wolverines, among others. Mustelids () are a diverse group and form the largest family in the suborder Caniformia of the order Carnivora. They comprise about 66 to 70 species in nine subfamilies. Variety Mustelids vary greatly in size and behaviour. The smaller variants of the least weasel can be under in length, while the giant otter of Amazonian South America can measure up to and sea otters can exceed in weight. Wolverines can crush bones as thick as the femur of a moose to get at the marrow, and have been seen attempting to drive bears away from their kills. The sea otter uses rocks to break open shellfish to eat. Martens are largely arboreal, while European badgers dig extensive tunnel networks, called setts. Only one mustelid has been domesticated; the ferret. Tayra are also kept as pets (although they requ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 resembling animals as disparate as rabbits and rhinoceroses. Notoungulata are the largest group of South American native ungulates, with over 150 genera in 14 families having been described, divided into two major subgroupings, Typotheria and Toxodontia. Notoungulates first diversified during the Eocene. Their diversity declined during the Late Neogene, with only the large toxodontids persisting until the end of the Pleistocene. Collagen analysis suggests that notoungulates are closely related to litopterns, another group of South American ungulates, and their closest living relatives being perissodactyls (odd-toed ungulates), including rhinoceroses, tapirs and equines. but their relationships to other South American ungulates are uncertain. Sev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
