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Creodonts
Creodonta ("meat teeth") is a former order of extinct carnivorous placental mammals that lived from the early Paleocene to the late Miocene epochs in North America, Europe, Asia and Africa. Originally thought to be a single group of animals ancestral to the modern Carnivora, this order is now usually considered a polyphyletic assemblage of two different groups, the oxyaenids and the hyaenodonts, not a natural group. Oxyaenids are first known from the Palaeocene of North America, while hyaenodonts hail from the Palaeocene of Africa. Creodonts were the dominant carnivorous mammals from , peaking in diversity and prevalence during the Eocene. The first large, obviously carnivorous mammals appeared with the radiation of the oxyaenids in the late Paleocene. During the Paleogene, "creodont" species were the most abundant terrestrial carnivores in the Old World. In Oligocene Africa, hyaenodonts were the dominant group of large flesh-eaters, persisting until the middle of the Miocene. " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnassial Shear
Carnassials are paired upper and lower teeth modified in such a way as to allow enlarged and often self-sharpening edges to pass by each other in a shearing manner. This adaptation is found in carnivorans, where the carnassials are the modified fourth upper premolar and the first lower molar. These teeth are also referred to as sectorial teeth. Taxonomy The name carnivoran is applied to a member of the order Carnivora. Carnivorans possess a common arrangement of teeth called carnassials, in which the first lower molar and the last upper premolar possess blade-like enamel crowns that act similar to a pair of shears for cutting meat. This dental arrangement has been modified by adaptation over the past 60 million years for diets composed of meat, for crushing vegetation, or for the loss of the carnassial function altogether found in pinnipeds. Carnassial dentition Carnassial teeth are modified molars (and in the case of carnivorans premolars) which are adapted to allow for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarkastodon
''Sarkastodon'' ("meaty tooth") is an extinct genus of placental mammals from extinct subfamily Oxyaeninae within extinct family Oxyaenidae, that lived in Asia (in today's China and Mongolia) during the middle Eocene. It was a genus of large, carnivorous animals known only from a skull and jawbones. ''Sarkastodon'' was probably a hypercarnivore that preyed on large mammals in its range during the Middle Eocene, such as brontotheres, chalicotheres, and rhinoceroses. Its weight is estimated at , and its length at 3 m (10 ft). Discovery The type specimens of ''S. mongoliensis'' are known from Eocene deposits from the Irdin Manha Formation of Mongolia. Additional material referred to ''Sarkastodon'' is known from the Ulan Shireb beds ( from the holotype locality) of Inner Mongolia. These specimens were discovered by Walter W. Granger in 1930, on an expedition to the Gobi Desert. Palaeobiology ''Sarkastodon'' was a hypercarnivore, with hyaena-like dentition specialis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyaenodonta
Hyaenodonta (" hyena teeth") is an extinct order of hypercarnivorous placental mammals of clade Pan-Carnivora from mirorder Ferae. Hyaenodonts were important mammalian predators that arose during the early Paleocene in Europe and persisted well into the late Miocene. Characteristics Hyaenodonts are characterized by long, often disproportionately large skulls, slender jaws, and slim bodies. They generally ranged in size from 30 to 140 cm at the shoulder. While '' Simbakubwa kutokaafrika'' may have been up to (surpassing the modern polar bear in size), this estimate is suspect due to being based on skull-body size ratios derived from felids, which have much smaller skulls for their body size. Other large hyaenodonts include two close and later-surviving relatives of ''Simbakubwa'', '' Hyainailouros'' and '' Megistotherium'' (the latter likely being the largest in the group), and the much earlier-living '' Hyaenodon gigas'' (the largest species from genus '' Hyaenodo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleocene
The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name is a combination of the Ancient Greek ''palaiós'' meaning "old" and the Eocene Epoch (which succeeds the Paleocene), translating to "the old part of the Eocene". The epoch is bracketed by two major events in Earth's history. The K–Pg extinction event, brought on by an asteroid impact (Chicxulub impact) and possibly volcanism (Deccan Traps), marked the beginning of the Paleocene and killed off 75% of species, most famously the non-avian dinosaurs. The end of the epoch was marked by the Paleocene–Eocene Thermal Maximum (PETM), which was a major climatic event wherein about 2,500–4,500 gigatons of carbon were released into the atmosphere and ocean systems, causing a spike in global temperatures and ocean acidification. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilisations. Its 4.7 billion people constitute roughly 60% of the world's population. Asia shares the landmass of Eurasia with Europe, and of Afro-Eurasia with both Europe and Africa. In general terms, it is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a social constructionism, historical and cultural construct, as there is no clear physical and geographical separation between them. A commonly accepted division places Asia to the east of the Suez Canal separating it from Africa; and to the east of the Turkish straits, the Ural Mountains an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Didymictis
''Didymictis'' ("double weasel") is an extinct genus of placental mammals from extinct subfamily Didymictinae within extinct family Viverravidae, that lived in North America and Europe from the late Paleocene to middle Eocene. Description ''Didymictis'' is the only viverravid genus for which there are considerable postcranial remains. The genus was primarily terrestrial but at least partly cursorial, similar to a civets. ''Didymictis'' had an elongated and relatively large skull with small and low braincase and a long and narrow basicranial region. The occipital and sagittal crests are very high. The limbs are of moderate length with subdigitigrade and five-toed feet. The dentition () contrasts those of basal carnivoraforms by the sharp differentiation between sectorial and tubercular dentition, the loss of the last molar and an elongated second molar, similar to the dentition in bears and raccoons. Comparing ''Didymictis'' to '' Vulpavus'', a much smaller and more agile carn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viverravidae
Viverravidae ("ancestors of viverrids") is an extinct monophyletic family of mammals from extinct superfamily Viverravoidea within the clade Carnivoramorpha, that lived from the early Palaeocene to the late Eocene in North America, Europe and Asia.Malcolm C. McKenna, Susan K. Bell: ''Classification of Mammals: Above the Species Level'' in Columbia University Press, New York (1997), 631 Seiten. They were once thought to be the earliest carnivorans and ancestral to extant ones, but now are placed outside the order Carnivora based on cranial morphology as relatives (a plesion-group) to extant carnivorans. General characteristics Wang and Tedford propose that they arose in North America 66–60 million years ago, spread to Asia then later to Europe, and were the first carnivoramorphans and possessed the first true pair of carnassial teeth.Wang, Xiaoming; Tedford, Richard H. (2008.) "Dogs: Their Fossil Relatives and Evolutionary History." New York: Columbia University Press In viv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is Cladogram#Homoplasies, homoplasy. The recurrent evolution of flight is a classic example, as flying pterygota, insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas ''homology (biology), homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different trai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypercarnivore
A hypercarnivore is an animal that has a diet that is more than 70% meat, either via active predation or by scavenging. The remaining non-meat diet may consist of non-animal foods such as fungi, fruits or other plant material. Some extant examples of hypercarnivorous animals include crocodilians, owls, shrikes, eagles, vultures, felids, most wild canids, polar bear, odontocetid cetaceans (toothed whales), snakes, spiders, scorpions, mantises, marlins, groupers, piranhas and most sharks. Every species in the family Felidae, including the domesticated cat, is a hypercarnivore in its natural state. Additionally, this term is also used in paleobiology to describe taxa of animals which have an increased slicing component of their dentition relative to the grinding component. In domestic settings, e.g. cats may have a diet derived from only plant and synthetic sources using modern processing methods. Feeding farmed animals such as alligators and crocodiles mostly or fully plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sister Group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and taxon B are sister groups to each other. Taxa A and B, together with any other extant or extinct descendants of their most recent common ancestor (MRCA), form a monophyletic group, the clade AB. Clade AB and taxon C are also sister groups. Taxa A, B, and C, together with all other descendants of their MRCA form the clade ABC. The whole clade ABC is itself a subtree of a larger tree which offers yet more sister group relationships, both among the leaves and among larger, more deeply rooted clades. The tree structure shown connects through its root to the rest of the universal tree of life. In cladistic standards, taxa A, B, and C may represent specimens, species, genera, or any other taxonomic units. If A and B are at the same taxono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dissopsalis
''Dissopsalis'' ('double scissors') is an extinct genus of hyaenodonts from extinct tribe Dissopsalini within family Teratodontidae. The older species, ''D. pyroclasticus'', lived in Kenya during the middle Miocene (15.0 to 9.0 Ma), while the type species, ''D. carnifex'', lived in Pakistan and India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ... during the middle to late Miocene (16.1 to 8.8 Ma).Barry, J. C. (1988.) "''Dissopsalis'', a middle and late Miocene proviverrine creodont (Mammalia) from Pakistan and Kenya." ''Journal of Vertebrate Paleontology'' 48(1): 25–45 ''Dissopsalis'' is the last known hyaenodont genus. References Hyaenodonts Miocene mammals of Africa Miocene mammals of Asia Prehistoric placental genera {{paleo-mammal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligocene
The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that 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 Ancient Greek (''olígos'') 'few' and (''kainós'') 'new', and refers to the sparsity of Neontology, extant forms of Mollusca, 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 chang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
