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Arctocyonidae
Arctocyonidae (from Greek ''arktos'' and ''kyôn'', "bear/dog-like") is an extinct, possibly polyphyletic family of placental mammals which lived from the late Cretaceous to the early Eocene. They were initially regarded as creodonts, though have since been reassigned to an order of their own, the Arctocyonia. Some have suggested that arctocyonids are ancestral to modern-day artiodactyls, or that they form a sister group. However, more recent phylogenetic analyses suggest that arctocyonids may represent an artificial grouping of extinct ungulates, or that they might be an assemblage of unrelated placentals related to pangolins, pantodonts, and periptychids. Members of Arctocyonidae are characterised by long skulls, with large sagittal crests and very large canines. In the case of '' Arctocyon'' proper, the lower canines especially were large enough to require a diastema on the upper jaw to accommodate them. Arctocyonids varied considerably in size and morphology. Smaller gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctocyoninae
Arctocyonidae (from Greek ''arktos'' and ''kyôn'', "bear/dog-like") is an extinct, possibly Polyphyly, polyphyletic Family (biology), family of Placentalia, placental mammals which lived from the late Cretaceous to the early Eocene. They were initially regarded as Creodonta, creodonts, though have since been reassigned to an Order (biology), order of their own, the Arctocyonia. Some have suggested that arctocyonids are ancestral to modern-day Artiodactyl, artiodactyls, or that they form a sister group. However, more recent Phylogenetics, phylogenetic analyses suggest that arctocyonids may represent an artificial grouping of extinct Ungulate, ungulates, or that they might be an assemblage of unrelated placentals related to Pangolin, pangolins, Pantodonta, pantodonts, and Periptychidae, periptychids. Members of Arctocyonidae are characterised by long skulls, with large Sagittal crest, sagittal crests and very large canines. In the case of ''Arctocyon'' proper, the lower canines es ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctocyon
''Arctocyon'' (from Greek ''arktos'' and ''kyôn'', "bear/dog-like") is an extinct genus of large placental mammals, part of the possibly polyphyletic family Arctocyonidae. The type species is ''A. primaevus'', though up to five other species may be known. Fossils of ''Arctocyon'' have been found in Europe and North America. ''Arctocyon'' was originally named as a subgenus of the bear-dog ''Amphicyon'', though was subsequently found to belong to a genus and family of its own. The relationship between arctocyonids and other placentals is unclear, with early classification efforts placing them as carnivores or creodonts, and later ones classifying them under Condylarthra, a wastebasket taxon for various early ungulates. More recent phylogenetic analyses suggest that arctocyonids are an artificial assemblage of several distantly-related placental lineages, and ''Arctocyon'' may be closely related to '' Loxolophus'' (another arctocyonid) and to pantodonts. ''Arctocyon'' was among the ... [...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] |
Anacodon
''Anacodon'' is a genus of arctocyonid from the Eocene of North America. It is known from the type species, ''A. ursidens'', a second species, ''A. cultridens'', and a possible third, ''A. nexus''. Initially believed to be a relative of '' Phenacodon'', it was subsequently found to be an arctocyonid, possibly related to '' Claenodon''. ''Anacodon'' was extremely robust compared to other members of its family, and may have been capable of climbing and digging like modern bears. Taxonomy Early history The first specimens of ''Anacodon'' to be discovered were a pair of mandibular rami, apparently from different individuals. In 1882, they were described by Edward Drinker Cope. Cope assigned the new genus to Phenacodontidae. Ten years later, in 1892, Henry Fairfield Osborn and Jacob Lawson Wortman instead assigned it to the family Arctocyonidae. In 1915, a second species of ''Anacodon'', ''A. cultridens'', was named by Walter Granger and William Diller Matthew. In 1937, George ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pantodonta
Pantodonta is an extinct suborder (or, according to some, an Order (biology), order) of eutherian mammals. These herbivorous mammals were one of the first groups of large mammals to evolve (around 66 million years ago) after the K-T boundary, end of the Cretaceous. The last pantodonts died out at the end of the Eocene (around 34 million years ago). Pantodonta include some of the largest mammals of their time, but were a diversified group, with some primitive members weighing less than and the largest more than . The earliest and most primitive pantodonts, ''Bemalambda'' (with a skull probably the size of a dog) and ''Hypsilolambda'', appear in the early Paleocene Shanghuan Formation in China. All more derived families are collectively classified as Eupantodonta. The pantodonts appear in North America in the middle Paleocene, where ''Coryphodon'' survived into the middle Eocene. Pantodont teeth have been found in South America (''Alcidedorbignya'') and Antarctica, and footprin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loxolophus
''Loxolophus'' is a genus of large arctocyonid from the early Palaeocene of North America. Two species are currently recognised: the type species, ''Loxolophus hyattianus'', and ''L. priscus''. Taxonomy Early history The holotype of ''Loxolophus'' (AMNH 3121), a fragment of the left maxilla, was formally described by Edward Drinker Cope in 1885. Cope initially assigned it to '' Chriacus'', and gave it the binomial name ''C. hyattianus''. In the same paper, a single page later, he described ''Loxolophus adapinus.'' Subsequently, they turned out to represent the same taxon, which at some point thereafter was recombined as ''Loxolophus hyattianus''. A second species, ''L. priscus'', was named three years after the initial paper, also by Cope, who similarly assigned it to ''Chriacus''. Subsequently, it was reassigned to ''Protochriacus'' by William Berryman Scott in 1892, then synonymised with ''Chriacus pugnax'' by George Gaylord Simpson in 1935, and finally was assigned to '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Creodonta
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] |
Arctocyonia
Arctocyonians (Arctocyonia; also known as "Procreodi") are a clade of laurasiatherian mammals whose stratigraphic range runs from the Palaeocene to the Early Eocene epochs. They were among the earliest examples of major mammalian predators after the Cretaceous–Paleogene extinction event. While some classify arctocyonians as stem-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 t ...s, others have classified the group as members of Ferae. There are three families classified in the order: Arctocyonidae, Oxyclaenidae, and Quettacyonidae. References Artiodactyls Paleocene first appearances Prehistoric mammals {{paleo-mammal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mentoclaenodon
''Mentoclaenodon'' is an extinct genus of arctocyonid ungulate mammals. ''Mentoclaenodon'' had large upper canines comparable to the "saber-teeth" of various Miocene and Pleistocene feliform saber-toothed cats. This genus and its sister-genus '' Anacodon'', and the oxyaenid ''Machaeroides ''were the first true mammals to develop saber-teeth. (The various saber-tooth gorgonopsian genera, such as ''Inostrancevia'' and ''Ruhuhucerberus'', are regarded as "stem-mammals" that are close relatives of true mammals). Fossils of ''Mentoclaenodon'' are found in late Paleocene-aged strata of Cernay, France, and in strata of Walbeck, Germany. The average estimated skull length is 15 cm. ''Mentoclaenodon'' is one of the largest European mammals during the Paleocene. It is also thought to be one of the earliest known Cenozoic-aged mammalian predators that would have preyed on other mammals. ''Mentoclaenodon ''and its ancestors reigned from the Cretaceous to the Paleocene. By the early ... [...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] |
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] |
Order (biology)
Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. An immediately higher rank, superorder, is sometimes added directly above order, with suborder directly beneath order. An order can also be defined as a group of related families. What does and does not belong to each order is determined by a taxonomist, as is whether a particular order should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognized only rarely. The name of an order is usually written with a capital letter. For some groups of organisms, their orders may follow consist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
