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Entelodont
Entelodontidae, the entelodonts, are an extinct family of pig-like artiodactyls (even-toed ungulates) which inhabited the Northern Hemisphere (Asia, Europe, and North America) from the late Eocene to the Middle Miocene epochs, about 38-19 million years ago. Their large heads, low snouts, narrow gait, and proposed omnivorous diet inspires comparisons to suids (true pigs) and tayassuids (peccaries), and historically they have been considered closely related to these families purely on a morphological basis. However, studies which combine morphological and molecular (genetic) data on artiodactyls instead suggest that entelodonts are cetancodontamorphs, more closely related to hippos and cetaceans than to pigs or other ungulates. Description Entelodonts could get quite large, and in many cases are the largest mammals in their respective ecosystems. The largest entelodont known from a complete skeleton was '' Daeodon'', a North American entelodont which could reach an estimated we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daeodon
''Daeodon'' is an extinct genus of entelodont even-toed ungulates that inhabited North America about 23 to 20 million years ago during the latest Oligocene and earliest Miocene. The type species is ''Daeodon shoshonensis'', described by a very questionable holotype by Cope. Some authors synonimize it with ''Dinohyus hollandi'' and several other species (see below), but due to the lack of diagnostic material, this is questionable at best. Another large member of this family, similar in size to ''Daeodon'', is the Asian '' Paraentelodon,'' but it is known by very incomplete material. Taxonomy The genus ''Daeodon'' was erected by the American anatomist and paleontologist Edward Drinker Cope in 1878. He classified it as a perissodactyl and thought that it was closely related to '' Menodus''. This classification persisted until the description of ''" Elotherium" calkinsi'' in 1905, a very similar and much more complete animal from the same rocks, which was promptly assigned ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeotherium Mortoni 01
''Archaeotherium'' ( grc, αρχαιοθήριον, meaning "ancient beast") is an extinct genus of entelodont artiodactyl endemic to North America during the Eocene and Oligocene epochs (35—28 mya), existing for approximately . ''Archaeotherium'' fossils are most common in the White River Formation of the Great Plains, but it has also been found in the John Day Basin of Oregon and the Trans-Pecos area of Texas. Taxonomy ''Archaeotherium'' was named by Joseph Leidy (1850Its type is ''Archaeotherium mortoni''. It was synonymized subjectively with ''Entelodon'' by Leidy (1853) and synonymized subjectively with ''Elotherium'' by Leidy (1857). It was assigned to Entelodontidae by Leidy (1850), Peterson (1909), Scott (1940), Galbreath (1953), Russell (1980), Carroll (1988) and Effinger (1998). ''Archaeotherium'', along with all other Entelodontidae, is an artiodactyl whose exact taxonomic position has been disputed, but taxonomists agree the group lies between the Suina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entelodon
''Entelodon'' (meaning "complete teeth", from Ancient Greek ''entelēs'' "complete" and ''odōn'' "tooth", referring to its "complete" eutherian dentition), is an extinct genus of entelodont artiodactyl endemic to Eurasia. Fossils of species are found in Paleogene strata ranging in age from the Houldjinian (37.2–33.9 mya) until the Rupelian epoch of the early Oligocene (33.9–28.4 mya). Taxonomy It is one of four entelodont genera native to Eurasia, the other three being the primitive ''Eoentelodon'' of late Eocene China, '' Proentelodon'' of middle Eocene Mongolia and the gigantic '' Paraentelodon'' of mid to late Oligocene Central Asia. Description ''Entelodon'' was a fairly typical entelodont, with a large, bulky body, slender legs, and a long snout. Like other entelodonts, ''Entelodon'' had complete eutherian dentition (3 incisors, 1 canine, 3 premolars, and 3 molars per quadrant). It had only two toes on each foot, and its legs were built for fast running.Agus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraentelodon
''Paraentelodon'' is an extinct entelodont from the Late Oligocene and Oligocene-Miocene boundary of Asia. The fossils of the type species ''P. intermedium'' were found in Georgia, Kazakhstan and China. An indeterminate species represents in Bugti Hills which is the late Oligocene of Pakistan.G. Métais, P.-O. Antoine, L. Marivaux, J.-L. Welcomme, and S. Ducrocq. 2003New artiodactyl ruminant mammal from the late Oligocene of Pakistan Acta Palaeontologica Polonica 48(3):375-382 Discovery and naming ''Paraentelodon'' was named by L. K. Gabunia in 1964 basing on molars and canine teeth that were found in Oligocene sites of Benara, Georgia (Georgian SSR at the time of discovery). It was assigned to Entelodontidae by Carroll (1988). In 1996 Lucas and Emry found ''Neoentelodon'' to be synonymous with ''Paraentelodon''. Although Gabunia did not explain the etymology, the name ''Paraentelodon'' is derived from the Greek ''para''/παρα "beside" or "near", ἐντελής en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Genetics
Molecular genetics is a sub-field of biology that addresses how differences in the structures or expression of DNA molecules manifests as variation among organisms. Molecular genetics often applies an "investigative approach" to determine the structure and/or function of genes in an organism's genome using genetic screens. The field of study is based on the merging of several sub-fields in biology: classical Mendelian inheritance, cellular biology, molecular biology, biochemistry, and biotechnology. Researchers search for mutations in a gene or induce mutations in a gene to link a gene sequence to a specific phenotype. Molecular genetics is a powerful methodology for linking mutations to genetic conditions that may aid the search for treatments/cures for various genetics diseases. History For molecular genetics to develop as a discipline, several scientific discoveries were necessary. The discovery of DNA as a means to transfer the genetic code of life from one ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cetancodontamorpha
Cetancodontamorpha is a total clade of artiodactyls defined, according to Spaulding ''et al''., as Whippomorpha "plus all extinct taxa more closely related to extant members of Whippomorpha than to any other living species". Attempts have been made to rename the clade Whippomorpha to Cetancodonta, but the former maintains precedent. Whippomorpha is the crown clade containing Cetacea (whales, dolphins, etc.) and hippopotamuses. According to Spaulding ''et al''., members of the whippomorph stem group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ... (i.e., "stem-whippomorphs") include such taxa as the family Entelodontidae and the genus '' Andrewsarchus''. References Cetruminantia Phylogenetics Taxa described in 2009 {{eventoedungulate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hippopotamus
The hippopotamus ( ; : hippopotamuses or hippopotami; ''Hippopotamus amphibius''), also called the hippo, common hippopotamus, or river hippopotamus, is a large semiaquatic mammal native to sub-Saharan Africa. It is one of only two extant species in the family Hippopotamidae, the other being the pygmy hippopotamus (''Choeropsis liberiensis'' or ''Hexaprotodon liberiensis''). Its name comes from the ancient Greek for "river horse" (). Aside from elephants and rhinos, the hippopotamus is the largest land mammal. It is also the largest extant land artiodactyl. Despite their physical resemblance to pigs and other terrestrial even-toed ungulates, the closest living relatives of the hippopotamids are cetaceans (whales, dolphins, porpoises, etc.), from which they diverged about 55 million years ago. Hippos are recognisable for their barrel-shaped torsos, wide-opening mouths with large canine tusks, nearly hairless bodies, pillar-like legs, and large size: adults average ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cetacea
Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel themselves through the water with powerful up-and-down movement of their tail which ends in a paddle-like fluke, using their flipper-shaped forelimbs to maneuver. While the majority of cetaceans live in marine environments, a small number exclusively reside in brackish water or fresh water. Having a cosmopolitan distribution, they can be found in some rivers and all of Earth's oceans, and many species inhabit vast ranges where they migrate with the changing of the seasons. Cetaceans are famous for their high intelligence and complex social behaviour as well as for the enormous size of some of the group's members, such as the blue whale which reaches a maximum confirmed length of 29.9 meters (98 feet) and a weight of 173 tonnes (190 short t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygomatic Arch
In anatomy, the zygomatic arch, or cheek bone, is a part of the skull formed by the zygomatic process of the temporal bone (a bone extending forward from the side of the skull, over the opening of the ear) and the temporal process of the zygomatic bone (the side of the cheekbone), the two being united by an oblique suture (the zygomaticotemporal suture); the tendon of the temporal muscle passes medial to (i.e. through the middle of) the arch, to gain insertion into the coronoid process of the mandible (jawbone). The jugal point is the point at the anterior (towards face) end of the upper border of the zygomatic arch where the masseteric and maxillary edges meet at an angle, and where it meets the process of the zygomatic bone. The arch is typical of '' Synapsida'' (“fused arch”), a clade of amniotes that includes mammals and their extinct relatives, such as '' Moschops'' and '' Dimetrodon''. Structure The zygomatic process of the temporal arises by two roots: * an '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (biology)
Morphology is a branch of biology dealing with the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance ( shape, structure, colour, pattern, size), i.e. external morphology (or eidonomy), as well as the form and structure of the internal parts like bones and organs, i.e. internal morphology (or anatomy). This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of gross structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Friedr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
