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Oxetocyon
''Oxetocyon'' ("beginning dog") is an extinct monospecific genus of the Borophaginae subfamily of canids native to North America. It lived during the Early Oligocene epoch, existing for approximately . Fossils have been found in Nebraska and South Dakota. Fossils of ''Oxetocyon'' are rare and, as a result, the genus is poorly known, and only the teeth, dentaries, and a fragmentary skull have been reported. The teeth of ''Oxetocyon'' indicate a hypocarnivorous diet, as is found in the living raccoon dog, and suggest a potential relationship to the unusual borophagine ''Otarocyon ''Otarocyon'' ("large eared dog") is an extinct genus of the Borophaginae subfamily of canids native to North America. It lived during the Oligocene epoch, about 34—30 Ma (million years ago). Fossils have been found only in Montana, Wyoming ...''. ''Oxetocyon'' is distinguished from ''Otarocyon'' by its own set of dental specializations for an omnivorous diet, particularly by the presence of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borophaginae
The extinct Borophaginae form one of three subfamilies found within the canid family. The other two canid subfamilies are the extinct Hesperocyoninae and extant Caninae. Borophaginae, called "bone-crushing dogs", were endemic to North America during the Oligocene to Pliocene and lived roughly 34—2.5 million years ago, existing for about . Origin The Borophaginae descended from the subfamily Hesperocyoninae. The earliest and most primitive borophagine is the genus ''Archaeocyon'', which is a small fox-sized animal mostly found in the fossil beds in western North America. The borophagines soon diversified into several major groups. They evolved to become considerably larger than their predecessors, and filled a wide range of niches in late Cenozoic North America, from small omnivores to powerful, bear-sized carnivores, such as ''Epicyon''. Species There are 66 identified borophagine species, including 18 new ones that range from the Orellan to Blancan ages. A phylogenetic anal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypocarnivore
A hypocarnivore is an animal that consumes less than 30% meat for its diet, the majority of which consists of fungi, fruits, and other plant material. Examples of living hypocarnivores are the grizzly bear (''Ursus horribilis''), black bear (''Ursus americanus''), binturong (''Arctictis binturong''), kinkajou (''Potos flavus''), and humans (''Homo sapiens''). The evolutionary division of carnivory into three groups, including hypercarnivore and mesocarnivore, appears to have occurred about 40 million years ago (mya). The term hypocarnivory is used with increasing frequency in describing early Canidae evolution, and reliance upon that survival strategy has a documented history in North American Borophaginae during the Miocene (23.03 to 5.33 mya). Twenty-five species of hypocarnivore are documented as co-occurring on the North American continent 30 mya. A shift from hyper- to hypo- occurred at least three times among Oligocene and Miocene canids ''Oxetocyon'', ''Phlaocyon'', and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monotypic Taxon
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispecific" or "monospecific" is sometimes preferred. In botanical nomenclature, a monotypic genus is a genus in the special case where a genus and a single species are simultaneously described. In contrast, an oligotypic taxon contains more than one but only a very few subordinate taxa. Examples Just as the term ''monotypic'' is used to describe a taxon including only one subdivision, the contained taxon can also be referred to as monotypic within the higher-level taxon, e.g. a genus monotypic within a family. Some examples of monotypic groups are: Plants * In the order Amborellales, there is only one family, Amborellaceae and there is only one genus, '' Amborella'', and in this genus there is only one species, namely ''Amborella trichopoda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleogene Mammals Of North America
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] |
Oligocene Carnivorans
The Oligocene ( ) is a geologic epoch of the Paleogene Period and 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 the Ancient Greek (''olígos'', "few") and (''kainós'', "new"), and refers to the sparsity of extant forms of 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 changes during the Oligocene included a global expansion of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molar (tooth)
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone tooth", from ''mola'', millstone and ''dens'', tooth. Molars show a great deal of diversity in size and shape across mammal groups. The third molar of humans is sometimes vestigial. Human anatomy In humans, the molar teeth have either four or five cusps. Adult humans have 12 molars, in four groups of three at the back of the mouth. The third, rearmost molar in each group is called a wisdom tooth. It is the last tooth to appear, breaking through the front of the gum at about the age of 20, although this varies from individual to individual. Race can also affect the age at which this occurs, with statistical variations between groups. In some cases, it may not even erupt at all. The human mouth contains upper (maxillary) and lower (mandib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentition
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology (that is, the relationship between the shape and form of the tooth in question and its inferred function) of the teeth of an animal. Animals whose teeth are all of the same type, such as most non-mammalian vertebrates, are said to have '' homodont'' dentition, whereas those whose teeth differ morphologically are said to have '' heterodont'' dentition. The dentition of animals with two successions of teeth (deciduous, permanent) is referred to as ''diphyodont'', while the dentition of animals with only one set of teeth throughout life is ''monophyodont''. The dentition of animals in which the teeth are continuously discarded and replaced throughout life is termed ''polyphyodont''. The dentition of animals in which the teeth are set in so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otarocyon
''Otarocyon'' ("large eared dog") is an extinct genus of the Borophaginae subfamily of canids native to North America. It lived during the Oligocene epoch, about 34—30 Ma (million years ago). Fossils have been found only in Montana, Wyoming, and South Dakota. ''Otarocyon'' was a small borophagine characterized by a short, broad skull, a specialized middle ear, simple, tall premolar teeth, and molars that are incipiently adapted to a hypocarnivorous diet. Despite its Oligocene age, the skull of ''Otarocyon'' shows several striking similarities to the living fennec fox, particularly in the structure of its middle ear. The similarities are probably convergent, but they suggest that ''Otarocyon'' may have been similar in its appearance and habits. Species *''O. macdonaldi'' Wang ''et al.'' 1999, Early Oligocene *''O. cooki'' Macdonald 1963, Late Oligocene In addition to its earlier age, ''O. macdonaldi'' differs from ''O. cooki'' in being smaller and in showing lesser devel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raccoon Dog
The common raccoon dog (''Nyctereutes procyonoides''), also called the Chinese or Asian raccoon dog, is a small, heavy-set, fox-like canid native to East Asia. Named for its raccoon-like face markings, it is most closely related to foxes. Common raccoon dogs feed on many animals and plant matter, and are unusual among canids (dogs, foxes, and other members of the family Canidae) for climbing trees and for hibernating in cold winters. They are widespread in their native range, and are invasive in Europe where they were introduced for the fur trade. The similar Japanese raccoon dog (''Nyctereutes viverrinus''), native to Japan, is the only other living member of the genus ''Nyctereutes''. Other names for the common raccoon dog include ''mangut'' (its Evenki name), ''neoguri'' (its Korean name) or simply raccoon dog. The raccoon dog is named for the resemblance of its masked face to that of the North American common raccoon (''Procyon lotor''). The closest relatives of the raccoon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, these two parts are the neurocranium and the viscerocranium ( facial skeleton) that includes the mandible as its largest bone. The skull forms the anterior-most portion of the skeleton and is a product of cephalisation—housing the brain, and several sensory structures such as the eyes, ears, nose, and mouth. In humans these sensory structures are part of the facial skeleton. Functions of the skull include protection of the brain, fixing the distance between the eyes to allow stereoscopic vision, and fixing the position of the ears to enable sound localisation of the direction and distance of sounds. In some animals, such as horned ungulates (mammals with hooves), the skull also has a defensive function by providing the mount (on the front ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentary
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movable bone of the skull (discounting the ossicles of the middle ear). It is connected to the temporal bones by the temporomandibular joints. The bone is formed prenatal development, in the fetus from a fusion of the left and right mandibular prominences, and the point where these sides join, the mandibular symphysis, is still visible as a faint ridge in the midline. Like other symphyses in the body, this is a midline articulation where the bones are joined by fibrocartilage, but this articulation fuses together in early childhood.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, p. 59 The word "mandible" derives from the Latin word ''mandibula'', "jawbone" (literally "one used for chewing"), from ''wikt:mandere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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