|
Josephoartigasia
''Josephoartigasia'' is an extinct genus of enormous dinomyid rodent from the Early Pliocene to Early Pleistocene of Uruguay. The only living member of Dinomyidae is the pacarana. ''Josephoartigasia'' is named after Uruguayan national hero José Artigas. It contains two species: ''J. magna'', described in 1966 based on a left mandible, and ''J. monesi'', described in 2008 based on a practically complete skull. Both are reported from the San José Member of the Raigón Formation by the Barrancas de San Gregorio along the shores of Kiyú beach. The skull of ''J. monesi'' measures , similar to a beef cow skull, equating to a full body length of —though this is likely an overestimate—and a weight of about . This makes ''J. monesi'' the biggest rodent ever discovered. It was much larger than ''J. magna'', giant hutia or the largest living rodent, the capybara, which averages . ''J. monesi'' also had a massive bite force of approximately at the incisors (on par with large car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinomyidae
The Dinomyidae are a family (biology), family of South American hystricognath rodents: the dinomyids were once a very speciose group, but now contains only a single living species, the pacarana. Several of the extinct dinomyids were among the largest rodents known to date; these included the bison-sized ''Josephoartigasia monesi'' and the smaller ''Josephoartigasia magna''. The dinomyids are thought to have occupied ecological niches associated with large grazing mammals due to their ability to compete with the Meridiungulata, native ungulates of South America. On the other side, they could feed on aquatic or swampy plants along the ancient rivers. These large forms disappeared after the formation of a Great American Interchange, connection to North America. The modern pacarana is only modest in size, considerably smaller than the capybara. The Neoepiblemidae, an entirely extinct family, may actually be part of the Dinomyidae; both groups are undoubtedly closely related. Genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chapadmalalan
The Chapadmalalan age is a period of geologic time (4.0–3.0 Ma) within the Pliocene epoch of the Neogene used more specifically with South American Land Mammal Ages. It follows the Montehermosan and precedes the Uquian age. Fossil content Fossils of '' Josephoartigasia magna'', a rodent in the family Dinomyidae from this age have been found in southern Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ....Francis, J. C. & Mones, A. (1966). ''Artigasia magna'' n. g., n. sp. (Eumegamyinae), un roedor gigantesco de la época Pliocena Superior de las Barrancas de San Gregorio, Departamento de San José, República Oriental del Uruguay. ''Kraglieviana'' 3, 89–100. References Neogene South America Pliocene life Piacenzian Zanclean {{geochronology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rodent
Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal species are rodents. They are native to all major land masses except for Antarctica, and several oceanic islands, though they have subsequently been introduced to most of these land masses by human activity. Rodents are extremely diverse in their ecology and lifestyles and can be found in almost every terrestrial habitat, including human-made environments. Species can be arboreal, fossorial (burrowing), saltatorial/ricochetal (leaping on their hind legs), or semiaquatic. However, all rodents share several morphological features, including having only a single upper and lower pair of ever-growing incisors. Well-known rodents include Mouse, mice, rats, squirrels, prairie dogs, porcupines, beavers, Cavia, guinea pigs, and hamsters. Once included wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capybara
The capybara or greater capybara (''Hydrochoerus hydrochaeris'') is the largest living rodent, native to South America. It is a member of the genus '' Hydrochoerus''. The only other extant member is the lesser capybara (''Hydrochoerus isthmius''). Its close relatives include guinea pigs and rock cavies, and it is more distantly related to the agouti, the chinchilla, and the nutria. The capybara inhabits savannas and dense forests, and lives near bodies of water. It is a highly social species and can be found in groups as large as one hundred individuals, but usually live in groups of 10–20 individuals. The capybara is hunted for its meat and hide and also for grease from its thick fatty skin. Etymology Its common name is derived from Tupi , a complex agglutination of (leaf) + (slender) + (eat) + (a suffix for agent nouns), meaning "one who eats slender leaves", or "grass-eater". The genus name, ''hydrochoerus'', comes from Greek (' "water") and (' "pig, hog") an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Álvaro Mones
Álvaro Jaime Mones Sibillotte (born 7 August 1942 in Montevideo) is a Uruguayan biologist and paleontologist. The fossil '' Josephoartigasia monesi
''Josephoartigasia'' is an extinct genus of enormous dinomyid rodent from the Early Pliocene to Early Pleistocene of Uruguay. The only living member of Dinomyidae is the pacarana. ''Josephoartigasia'' is named after Uruguayan national hero Jo ... '' is named after him, for his study of the rodent in 1966.
References 1942 births[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raigón Formation
The Raigón Formation is a geologic formation in Uruguay dated between the Pliocene and Middle Pleistocene. Overview In 1966, Uruguayan geologists Héctor Goso and Jorge Bossi defined the Raigón Formation, which they subdivided into the San José Member (the same as Francis and Mones' San José Formation) below and the San Bautista Member above. In 1988, Álvaro Mones identified Lower Pleistocene levels in the San José Member. In 2002, American geologist H. McDonald and Uruguayan paleontologist Daniel Perea suggested the formation may represent a wide timespan from the Montehermosan all the way to the Ensenadan. A notable finding was ''J. monesi'', recovered ''in situ'' from a boulder originating in the San José Member. The boulder is made up of siltstone, claystone, and medium- grained and medium-to- conglomeratic psammite (a type of sandstone) intercalated with siltstone. Fossil content The following fossils have been reported from the formation: * '' Charruatoxodon' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heptaxodontidae
Heptaxodontidae, rarely called giant hutia, is an extinct family (taxonomy), family of large rodents known from fossil and subfossil material found in the West Indies. One species, ''Blunt-toothed giant hutia, Amblyrhiza inundata'', is estimated to have weighed between , reaching the weight of an eastern gorilla. This is twice as large as the capybara, the largest rodent living today, but still much smaller than ''Josephoartigasia monesi'', the largest rodent known. These animals were probably used as a food source by the pre-Columbian peoples of the Caribbean. Heptaxodontidae contains no living species and the grouping seems to be paraphyletic and arbitrary, however. One of the smaller species, ''Twisted-toothed mouse, Quemisia gravis'', may have survived as late as when the Spanish began to colonize the Caribbean. Despite the vernacular name, heptaxodontids are not closely related to the extant hutias of the family Echimyidae. Heptaxodontids are thought to be more closely rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacarana
The pacarana (''Dinomys branickii'') is a rare and slow-moving hystricognath rodent indigenous to South America. Native Tupi people call it the ''pacarana'' (false paca) because it is superficially similar to the paca, a different rodent which is not in the same family. The pacarana has a chunky body and is large for a rodent, weighing up to and measuring up to in length, not including the thick, furry tail. The pacarana is nocturnal and is found only in tropical forests of the western Amazon River basin and adjacent foothills of the Andes Mountains. It ranges from northwestern Venezuela and Colombia to western Bolivia, including the Yungas. It is common in Cotapata National Park in Bolivia. The pacarana is the sole extant member of the rodent family Dinomyidae in the infraorder Caviomorpha; the paca that it resembles in appearance is in a different Caviomorph family, the Cuniculidae. Initially, the pacarana was regarded as a member of the superfamily Muroidea The Muroid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress (mechanics)
In continuum mechanics, stress is a physical quantity that describes forces present during deformation. For example, an object being pulled apart, such as a stretched elastic band, is subject to ''tensile'' stress and may undergo elongation. An object being pushed together, such as a crumpled sponge, is subject to ''compressive'' stress and may undergo shortening. The greater the force and the smaller the cross-sectional area of the body on which it acts, the greater the stress. Stress has dimension of force per area, with SI units of newtons per square meter (N/m2) or pascal (Pa). Stress expresses the internal forces that neighbouring particles of a continuous material exert on each other, while ''strain'' is the measure of the relative deformation of the material. For example, when a solid vertical bar is supporting an overhead weight, each particle in the bar pushes on the particles immediately below it. When a liquid is in a closed container under pressure, each ... [...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] |
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 the 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 among individuals and populations, and in many cases the tooth is missing. The human mouth contains upper (maxillary) and lower (mandibular) molars. They are: maxillary first molar, maxillary second molar, maxillary third mol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocodilia
Crocodilia () is an order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorph pseudosuchian, a subset of archosaurs that appeared about 235 million years ago and were the only survivors of the Triassic–Jurassic extinction event. While other crocodylomorph groups further survived the Cretaceous–Paleogene extinction event, notably sebecosuchians, only the crocodilians have survived into the Quaternary. The order includes the true crocodiles (family Crocodylidae), the alligators and caimans (family Alligatoridae), and the gharial and false gharial (family Gavialidae). Although the term "crocodiles" is sometimes used to refer to all of these families, the term "crocodilians" is less ambiguous. Extant crocodilians have flat heads with long snouts and tails that are compressed on the sides, with their eyes, ears, and n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
