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Mesonychia
Mesonychia ("middle claws") is an extinct taxon of small to large-sized carnivorous ungulates related to artiodactyls. Mesonychians first appeared in the early Paleocene, went into a sharp decline at the end of the Eocene, and died out entirely when the last genus, ''Mongolestes'', became extinct in the early Oligocene. In Asia, the record of their history suggests they grew gradually larger and more predatory over time, then shifted to scavenging and bone-crushing lifestyles before the group became extinct. Mesonychians probably originated in China, where the most primitive mesonychian, ''Yantanglestes'', is known from the early Paleocene. They were also most diverse in Asia, where they occur in all major Paleocene faunas. Since other predators, such as Creodonta, creodonts and Carnivora, were either rare or absent in these animal communities, mesonychians most likely dominated the large predator Ecological niche, niche in the Paleocene of eastern Asia. One genus, ''Dissacus'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ungulate
Ungulates ( ) are members of the diverse clade Euungulata ("true ungulates"), which primarily consists of large mammals with Hoof, hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined to be a polyphyletic and thereby invalid clade based on molecular data. As a result, true ungulates had since been reclassified to the newer clade Euungulata in 2001 within the clade Laurasiatheria while Paenungulata has been reclassified to a distant clade Afrotheria. Living ungulates are divided into two orders: Perissodactyla including Equidae, equines, rhinoceroses, and tapirs; and Artiodactyla including Bos, cattle, antelope, Sus (genus), pigs, giraffes, camels, Ovis, sheep, deer, and Hippopotamidae, hippopotamuses, among others. Cetaceans such as Whale, whales, Dolphin, dolphins, and Porpoise, porpoises are also classified as artiodactyls, although they do not have hooves. Most terrestrial ungulates use the hoofed tips of their toes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnivora
Carnivora ( ) is an order of placental mammals specialized primarily in eating flesh, whose members are formally referred to as carnivorans. The order Carnivora is the sixth largest order of mammals, comprising at least 279 species. Carnivorans are found on every major landmass and in a variety of habitats, ranging from the cold polar regions of Earth to the hyper-arid region of the Sahara Desert and the open seas. Carnivorans exhibit a wide array of body plans, varying greatly in size and shape. Carnivora are divided into two suborders, the Feliformia, containing the true felids and several animals; and the Caniformia, containing the true canids and many animals. The feliforms include the Felidae, Viverridae, hyena, and mongoose families, the majority of which live only in the Old World; cats are the only exception, occurring in the Old World and the New World, entering the Americas via the Bering land bridge. The caniforms include the Caninae, Procyonidae, bears, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesonyx Model Reconstruction At The Natural History Museum, London
''Mesonyx'' ("middle claw") is a genus of extinct mesonychid mesonychian mammal. Fossils of the various species are found in Early to Late Eocene-age strata in the United States and Early Eocene-aged strata in China, 51.8—51.7 Ma ( AEO). Description ''Mesonyx'' species have been estimated as 1.25-1.5m (4.5–5 ft.) long in life, not including the tail. Weight estimates vary, from 20 to 55 kg (about 45-120 lbs). Like other mesonychids, the toes ended in small hooves. Like other mesonychids, they had large heads and long necks in proportion to their body size, and cranial material is most often preserved. ''Mesonyx uintensis'' from the Upper Eocene of Wyoming is described as having a total cranium length of 429 mm. (17 inches) and a facial length of 206 mm (8 inches). The long skull had a relatively large sagittal crest above the braincase to anchor large jaw muscles and give it a powerful bite. Brain casts show that ''M. obtusidens'' had an unusually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artiodactyl
Artiodactyls are placental mammals belonging to the order Artiodactyla ( , ). Typically, they are ungulates which bear weight equally on two (an even number) of their five toes (the third and fourth, often in the form of a hoof). The other three toes are either present, absent, vestigial, or pointing posteriorly. By contrast, most perissodactyls bear weight on an odd number of the five toes. Another difference between the two orders is that many artiodactyls (except for Suina) digest plant cellulose in one or more stomach chambers rather than in their intestine (as perissodactyls do). Molecular biology, along with new fossil discoveries, has found that cetaceans (whales, dolphins, and porpoises) fall within this taxonomic branch, being most closely related to hippopotamuses. Some modern taxonomists thus apply the name Cetartiodactyla () to this group, while others opt to include cetaceans within the existing name of Artiodactyla. Some researchers use "even-toed ungulates" t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triisodontidae
Triisodontidae is an extinct, probably paraphyletic, or possibly invalid family of mesonychian placental mammals. Most triisodontid genera lived during the Paleocene in North America, but the genus ''Andrewsarchus'' (if it is a mesonychian, and not an artiodactyl) is known from the middle Eocene of Asia. Triisodontids were the first relatively large predatory mammals to appear in North America following the extinction of the non-bird dinosaurs. They differ from other mesonychian families in having less highly modified teeth. Because of their comparatively simpler teeth, the triisodontids are regarded as basal mesonychids. A recent study found them to be a paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ... assemblage of stem-mesonychians.Sarah L. Shelley, Thomas E. Wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachyaena
''Pachyaena'' (literally, "thick hyena") was a genus of heavily built, relatively short-legged mesonychids, early Cenozoic mammals that evolved before the origin of either modern hoofed animals or carnivores, and combined characteristics similar to both. The genus likely originated from Asia and spread to Europe, and from there to North America across a land bridge in what is now the North Atlantic ocean. Various described species of ''Pachyaena'' ranged in size from a coyote to a bear. However, a 2007 paper suggests that ''Pachyaena'' may be paraphyletic, with ''P. ossifraga'' being closer to '' Synoplotherium'', '' Harpagolestes'' and '' Mesonyx'' than to ''P. gigantea''. Unlike many mesonychids, ''Pachyaena'' is known from skeletal material in addition to skulls and jaws. Analysis of three wolf- to bear-sized species from the early Eocene of Wyoming ( Willwood formation) indicates they all had many adaptations for running, including paraxonic compressed feet with a vesti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dissacus
''Dissacus'' is a genus of extinct carnivorous jackal to coyote-sized mammals within the family Mesonychidae, an early group of hoofed mammals that evolved into hunters and omnivores. Their fossils in Paleocene to Early Eocene aged strata in France, Asia and southwest North America, from 66 to 50.3 mya, existed for approximately . Orientation patch analysis of the molar teeth of the North American ''D. praenuntius'' suggests it was an omnivore that ate a lot of meat, not an exclusive meat-eater like a cat or weasel. It shared its environment with more omnivorous mammals of a similar body size. Though they are not ancestral to Carnivora, ''Dissacus'' species may have had similar roles in Paleocene-early Eocene environments as the foxes and other small canids that evolved later: generalised hunters who also ate fruit or other foods, and caught small animals that lived on the ground. The bear-sized '' Ankalagon'' is closely related to ''Dissacus''. Some palaeontologists consider ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harpagolestes Immanis
''Harpagolestes'' ("hooked thief") is an extinct genus of hyena like, bear sized mesonychid mesonychian that lived in Central and Eastern Asia and western and central North America during the middle to late Eocene. It has been suggested that ''Harpagolestes'' is a wastebasket genus for fragmentary Eocene mesonychids. Description ''Harpagolestes'' was a large animal, with a skull length of a half a meter in some species. Fossil specimens have been recovered in the United States, Canada, Mongolia, China, and controversially North Korea. ''Harpagolestes'' exhibits strong, curved canine teeth, a deep lower jaw, massive skull, and heavy wear on the molars. This along with stout limb bones suggest that ''Harpagolestes'' was a scavenger Scavengers are animals that consume Corpse decomposition, dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a he . ... [...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] |
Ankalagon
''Ankalagon saurognathus'' is an extinct carnivorous mammal of the family (biology), family Mesonychidae, endemic to North America during the Paleocene epoch (63.3—60.2 Myr, mya), existing for approximately . Known from the Paleocene Nacimiento Formation of New Mexico, ''Ankalagon'' is the largest Mesonychidae, mesonychid known from the Paleocene of North America, and it provides the best evidence for sexual dimorphism in mesonychids. Taxonomy The generic name refers to the dragon Dragon (Middle-earth), Ancalagon, who was mentioned in ''The Silmarillion'' by J. R. R. Tolkien. In ''The Silmarillion'', Ancalagon was described as being one of the more powerful servants of the malevolent being, Morgoth, having been bred to be the fiercest, mightiest, and largest dragon in all of Middle-earth. According to Tolkien, "Ancalagon" translates from Sindarin as being ''anc'' 'jaw', ''alag'' 'impetuous'. The species name, "''saurognathus''," translates as "lizard jaw." Leigh Van Valen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hapalodectidae
Hapalodectidae (literal translation 'soft biters': ('soft, tender'), ('biter')) is an extinct family of relatively small-bodied () mesonychian placental mammals from the Paleocene and Eocene of North America and Asia. Hapalodectids differ from the larger and better-known mesonychids by having teeth specialized for cutting (presumably meat), while the teeth of other mesonychids, such as '' Mesonyx'' or ''Sinonyx'', are more specialized for crushing bones. Hapalodectids were once considered a subfamily of the Mesonychidae, but the discovery of a skull of '' Hapalodectes hetangensis'' showed additional differences justifying placement in a distinct family. In particular, ''H. hetangensis'' has a postorbital bar closing the back of the orbit, a feature lacking in mesonychids. The postcranial skeletal anatomy of hapalodectids is poorly known, and of the postcranial elements, only the humerus The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
