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Xenosmilus With Concealed Canine
''Xenosmilus'' is an extinct genus of homotherin machairodontine (saber-toothed cat) that roamed the North America from the Early Pleistocene. The type species of the genus, ''X. hodsonae,'' is known from Early Pleistocene deposits in Florida. Over the recent years, scientists have proposed ''X. venezuelensis'' (formerly ''Homotherium venezuelensis'') could be a valid species within the genus, in addition to a possible third unnamed species, cf. ''Xenosmilus'' sp., from Uruguay. If valid, both species would extend the genus’ range into the Middle Pleistocene and South America. Taxonomy Discovery and Naming Two fairly intact specimens were found by amateur fossil hunters in 1983 (1981 by some sources) in the Haile limestone mines in Alachua County, Florida. The genus and type species, ''Xenosmilus hodsonae'', was described in 2001 based on a nearly complete skeleton (BIOPSI 101) from the Florida site Haile 21A, with a second partial skeleton (UF 60,000) as the paratype. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Pleistocene
The Early Pleistocene is an unofficial epoch (geology), sub-epoch in the international geologic timescale in chronostratigraphy, representing the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently estimated to span the time between 2.580 ± 0.005 annum, Ma (million years ago) and 0.773 ± 0.005 Ma. The term Early Pleistocene applies to both the Gelasian, Gelasian Age and the Calabrian (stage), Calabrian Age. While the Gelasian and the Calabrian have officially been defined by the International Union of Geological Sciences (IUGS) to effectively constitute the Early Pleistocene, the succeeding Chibanian and Tarantian ages have yet to be ratified. These proposed ages are unofficially termed the Middle Pleistocene and Late Pleistocene respectively. The Chibanian provisionally spans time from 773 ka to 126 ka, and the Tarantian from then until the definitive end of the whole Pleistocene, c. 9700 BC in the 10th millennium BC. Notes {{Ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homotherium
''Homotherium'' is an extinct genus of Homotherini, scimitar-toothed cat belonging to the extinct subfamily Machairodontinae that inhabited North America, Eurasia, and Africa, as well as possibly South America during the Pliocene and Pleistocene epochs from around 4 million to 12,000 years ago. It was one of the last surviving members of the subfamily alongside the more famous sabertooth ''Smilodon'', to which it was not particularly closely related. It was a large cat, comparable in size to a lion, functioning as an apex predator in the ecosystems it inhabited. It had an elongate neck and relatively elongate legs, a relatively short back and a very short tail, with the mummy of a ''H. latidens'' cub of Late Pleistocene age found in Siberia having a plain dark brown coat colour. In comparison to ''Smilodon'', the canines of ''Homotherium'' were shorter, though still longer than those of living cats, and it is suggested to have had a different ecology from ''Smilodon'' as a pursuit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megalonyx
''Megalonyx'' (Greek, "great-claw") is an extinct genus of ground sloths of the family Megalonychidae, native to North America. It evolved during the Pliocene Epoch and became extinct at the end of the Late Pleistocene, living from ~5 million to ~13,000 years ago. The type species, ''M. jeffersonii'' (also called Jefferson's ground sloth), the youngest and largest known species, measured about in length and weighed up to . ''Megalonyx'' is suggested to have descended from '' Pliometanastes,'' a genus of ground sloth that had arrived in North America during the Late Miocene around 9 million years ago, prior to the main phase of the Great American Interchange. ''Megalonyx'' had the widest distribution of any North American ground sloth, having a range encompassing most of the contiguous United States, extending as far north as Alaska during warm interglacial periods. ''Megalonyx'' is notable for having been originally described by future U.S. President Thomas Jefferson in 1799 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sociality
Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies. Sociality is a survival response to evolutionary pressures. For example, when a mother wasp stays near her larvae in the nest, parasites are less likely to eat the larvae. Biologists suspect that pressures from parasites and other predators selected this behavior in wasps of the family Vespidae. This wasp behaviour evidences the most fundamental characteristic of animal sociality: parental investment. Parental investment is any expenditure of resources (time, energy, social capital) to benefit one's offspring. Parental investment detracts from a parent's capacity to invest in future reproduction and aid to kin (including other offspring). An animal that cares for its young but shows no other sociality traits is said to be ''subsocial''. An animal that exhibits a high degree of sociality is called a ''social animal'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platygonus
''Platygonus'' ("flat head" in reference to the straight shape of the forehead) is an extinct genus of herbivorous peccaries of the family Tayassuidae, endemic to North and South America from the Miocene through Pleistocene epochs (10.3 million to 11,000 years ago), existing for about . ''P. compressus'' stood tall. Taxonomy While long thought to be the sister-lineage to the Chacoan peccary based on morphological similarities, a 2017 ancient DNA study which recovered mitochondrial DNA from ''Platygonus'' found that all living peccaries are more closely related to each other than they are to ''Platygonus''. The estimated divergence between ''Platygonus'' and all living peccaries was placed in the Miocene, around 22 million years ago. Description Most ''Platygonus'' species were similar in size to modern peccaries especially giant peccary, at around in body length, and had long legs, allowing them to run well. They also had a pig-like snout and long tusks which were prob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premolar
The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in the permanent teeth, permanent set of teeth, making eight premolars total in the mouth. They have at least two Cusp (dentistry), cusps. Premolars can be considered transitional teeth during chewing, or mastication. They have properties of both the canines, that lie anterior and molars that lie Posterior (anatomy), posterior, and so food can be transferred from the canines to the premolars and finally to the molars for grinding, instead of directly from the canines to the molars. Human anatomy The premolars in humans are the maxillary first premolar, maxillary second premolar, mandibular first premolar, and the mandibular second premolar. Premolar teeth by definition are permanent teeth Anatomical terms of location#Proximal and distal, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incisor
Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, whereas armadillos, anteaters and other animals in the order Edentata have none. Structure Adult humans normally have eight incisors, two of each type. The types of incisors are: * maxillary central incisor (upper jaw, closest to the center of the lips) * maxillary lateral incisor (upper jaw, beside the maxillary central incisor) * mandibular central incisor (lower jaw, closest to the center of the lips) * mandibular lateral incisor (lower jaw, beside the mandibular central incisor) Children with a full set of deciduous teeth (primary teeth) also have eight incisors, named the same way as in permanent teeth. Young children may have from zero to eight incisors depending on the stage of their tooth eruption and tooth development. Typic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fang
A fang is a long, pointed tooth. In mammals, a fang is a modified maxillary tooth, used for biting and tearing flesh. In snakes, it is a specialized tooth that is associated with a venom gland (see snake venom). Spiders also have external fangs, which are part of the chelicerae. Fangs are most common in carnivores or omnivores, but some herbivores, such as fruit bats, have them as well. They are generally used to hold or swiftly kill prey, such as in large cats. Omnivorous animals, such as bears, use their fangs when hunting fish or other prey, but they are not needed for consuming fruit. Some apes also have fangs, which they use for threats and fighting. However, the relatively short canines of humans are not considered to be fangs. Fangs in religion, mythology and legend Certain mythological and legendary creatures such as dragons, gargoyles, demons and yakshas are commonly depicted with prominent fangs. The fangs of vampires are one of their defining characteristics. The i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serration
Serration is a saw-like appearance or a row of sharp or tooth-like projections. A serrated cutting edge has many small points of contact with the material being cut. By having less contact area than a smooth blade or other edge, the applied pressure at each point of contact is greater, and the points of contact are at a sharper angle to the material being cut. This causes a cutting action that involves many small splits in the surface of the material being cut, which cumulatively serve to cut the material along the line of the blade. Serration in nature In nature, serration is commonly seen in the cutting edge on the teeth of some species, usually sharks. However, it also appears on non-cutting surfaces, for example, in botany where a toothed leaf margin or other plant part, such as the edge of a carnation petal, is described as being serrated. A serrated leaf edge may reduce the force of wind and other natural elements. Probably the largest serrations on Earth occur on the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canine Tooth
In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, eye teeth, vampire teeth, or fangs, are the relatively long, pointed teeth. In the context of the upper jaw, they are also known as '' fangs''. They can appear more flattened, however, causing them to resemble incisors and leading them to be called ''incisiform''. They developed and are used primarily for firmly holding food in order to tear it apart, and occasionally as weapons. They are often the largest teeth in a mammal's mouth. Individuals of most species that develop them normally have four, two in the upper jaw and two in the lower, separated within each jaw by incisors; humans and dogs are examples. In most species, canines are the anterior-most teeth in the maxillary bone. The four canines in humans are the two upper maxillary canines and the two lower mandibular canines. They are specially prominent in dogs (Canidae), hence the name. Details There are generally four canine teeth: two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smilodontini
Smilodontini is an extinct tribe within the Machairodontinae or "saber-toothed cat" subfamily of the Felidae. The tribe is also known as the "dirk-toothed cats". They were found in South America, North America, Europe, Asia, and Africa during the Middle Miocene to early Holocene, from 10.3 mya—8,200 years ago. As the name suggests, the famous genus of ''Smilodon'' is part of this group, but there are also three other distinct genera in Smilodontini. The earliest known genus of the tribe is '' Promegantereon'', once thought to be a species of '' Paramachairodus''. The tribe only became extinct 10,000 years ago, with the demise of ''Smilodon''. All of these are saber-toothed cats, meaning that they have long, narrow upper canines and stocky, well muscled proportions. Description The various members of Smilodontini are generally distinguished by their long, narrow upper canines. However, the stockiness often seen as one of the tribe's signature features varied between the differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smilodon
''Smilodon'' is an extinct genus of Felidae, felids. It is one of the best known saber-toothed predators and prehistoric mammals. Although commonly known as the saber-toothed tiger, it was not closely related to the tiger or other modern cats, belonging to the extinct subfamily Machairodontinae, with an estimated date of Speciation, divergence from the ancestor of living cats around 20 million years ago. ''Smilodon'' was one of the last surviving machairodonts alongside ''Homotherium''. ''Smilodon'' lived in the Americas during the Pleistocene to early Holocene epoch (2.5 Year#mya, mya – at latest 8,200 years ago). The genus was named in 1842 based on fossils from Brazil; the generic name means or combined with . Three species are recognized today: ''S. gracilis'', ''S. fatalis'', and ''S. populator''. The two latter species were probably descended from ''S. gracilis'', which itself probably evolved from ''Megantereon''. The hundreds of specimens obtained from the La Brea T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
