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Megalomys Audreyae
''Megalomys audreyae'', known as the Barbudan (?) muskrat or the Barbuda giant rice rat, is an extinct oryzomyine rodent from Barbuda in the Lesser Antilles. Described on the basis of a single mandible (lower jaw) with the first molar missing and an isolated upper incisor, both of uncertain but Quaternary age, it is one of the smaller members of the genus ''Megalomys''. Little is known about the animal, and its provenance and distinction from "''Ekbletomys hypenemus''", an even larger extinct oryzomyine that also occurred on Barbuda, have been called into question. The toothrow in the lower jaw has a length of 8.7 mm at the alveoli. The third molar is relatively narrow and both the second and third molars have a wide valley between their outer cusps. History Remains of ''Megalomys audreyae'' were found by John Walter Gregory among cave breccia on Barbuda around 1900. The exact locality is unknown. In his 1901 description of '' Oryzomys luciae'', Charles Immanuel Forsyth Majo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today, although a third epoch, the Anthropocene, has been proposed but is not yet officially recognised by the ICS). The Quaternary Period is typically defined by the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused. Research history In 1759 Giovanni Arduino proposed that the geological strata of northern Italy could be divided into four successive formations or "orders" ( it, quattro ordini). The term "quaternary" was introduced by Jules Desnoye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Immanuel Forsyth Major
Charles Immanuel Forsyth Major (15 August 1843, Glasgow – 25 March 1923, Munich) was a Scottish-born, Swiss physician, zoologist and vertebrate palaeontologist. Major was born in Glasgow and studied at Basel and Zurich Universities in Switzerland and later Göttingen in Germany. He graduated in medicine at Basel in 1868 and became a physician in Florence, Italy. Like many early naturalists he spent his free time studying fossil mammals. His first publication was on fossil primates in 1872. The Italian government supported him in 1877 and he collected fossils from Calabria, Corsica, Sardinia, and Sicily. In 1886, he stopped practising as a physician and began to study fossils in the Greek Archipelago with his collections going to the College Galliard at Lausanne and to the British Museum (Natural History). In the British Museum collections he took a keen interest in material from Madagascar. He studied the lemur fauna, both extant and extinct, discovered the new family Megaladap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoconid
Many different terms have been proposed for features of the tooth crown in mammals. The structures within the molars receive different names according to their position and morphology. This nomenclature was developed by Henry Fairfield Osborn in 1907 and is, although with many variations, the one that continues today. * The suffix "-cones /-conids" (upper molar/lower molar) is added to the main cusps: Paraconus, Metaconus, Protoconus and Hypoconus on the upper molar, and Paraconid, Metaconid, Protoconid, Hypoconid and Entoconid on the lower molar. This name is used for both bunodont and selenodont molars, that is, as many for "buno" pillar-like cusps as for "selenes" crescent-like cusps. * The suffix "-conule /-conulid" (upper molar/lower molar) is added to the secondary cusps. For example, Metaconule, Hypoconulid. * The suffix "-style/-stylid" (upper molar/lower molar) is added to the peripheral cusps that are found in the cornices or cingulus of the tooth. These cusps are tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dental Alveolus
Dental alveoli (singular ''alveolus'') are sockets in the jaws in which the roots of teeth are held in the alveolar process with the periodontal ligament. The lay term for dental alveoli is tooth sockets. A joint that connects the roots of the teeth and the alveolus is called ''gomphosis'' (plural ''gomphoses''). Alveolar bone is the bone that surrounds the roots of the teeth forming bone sockets. In mammals, tooth sockets are found in the maxilla, the premaxilla, and the mandible. Etymology 1706, "a hollow," especially "the socket of a tooth," from Latin alveolus "a tray, trough, basin; bed of a small river; small hollow or cavity," diminutive of alvus "belly, stomach, paunch, bowels; hold of a ship," from PIE root *aulo- "hole, cavity" (source also of Greek aulos "flute, tube, pipe;" Serbo-Croatian, Polish, Russian ulica "street," originally "narrow opening;" Old Church Slavonic uliji, Lithuanian aulys "beehive" (hollow trunk), Armenian yli "pregnant"). The word was extended in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capsular Process
In rodents, the capsular process or projection is a bony capsule that contains the root of the lower incisor. It is visible on the labial (outer) side of the mandible 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 teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ... (lower jaw) as a raising in the bone.Weksler, 2006, p. 41 There is marked variation within species in the development of this process.Steppan, 1995, p. 26 Most oryzomyines have a well-developed capsular process, which is usually located behind the coronoid process, but many have a small one, and some lack the structure entirely. Phyllotines and akodontines are also variable in their development of a capsular process.Steppan, 1995, table 4, char. 33 References {{reflist, colwidth=30em Literature cited * Steppan, S.J. 1995. Revision of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Process
Angular may refer to: Anatomy * Angular artery, the terminal part of the facial artery * Angular bone, a large bone in the lower jaw of amphibians and reptiles * Angular incisure, a small anatomical notch on the stomach * Angular gyrus, a region of the brain in the parietal lobe * Angular vein, formed by the junction of the frontal vein and supraorbital vein Other uses * Angular (web framework), an open-source web platform **AngularJS, the first incarnation of Angular * Angle, having an angle or angles * Angular diameter, describing how large a sphere or circle appears from a given point of view ** Angular diameter distance, used in astronomy * Angular Recording Corporation, a British independent record label See also * Angle (other) An angle is a figure formed by two rays or a measure of rotation. Angle may also refer to: Places United States * The Angle, in the American Civil War, an area of the Gettysburg battlefield * Angle Creek, a river in Alaska * Angle Townsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronoid Process Of The Mandible
In human anatomy, the mandible's coronoid process (from Greek ''korōnē'', denoting something hooked) is a thin, triangular eminence, which is flattened from side to side and varies in shape and size. Its anterior border is convex and is continuous below with the anterior border of the ramus. Its ''posterior border'' is concave and forms the anterior boundary of the mandibular notch. The ''lateral surface'' is smooth, and affords insertion to the temporalis and masseter muscles. Its ''medial surface'' gives insertion to the temporalis, and presents a ridge which begins near the apex of the process and runs downward and forward to the inner side of the last molar tooth. Between this ridge and the anterior border is a grooved triangular area, the upper part of which gives attachment to the temporalis, the lower part to some fibers of the buccinator. Clinical significance Fractures of the mandible are common. However, coronoid process fractures are very rare. Isolated fractures of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condyloid Process
The condyloid process or condylar process is the process on the human and other mammalian species' mandibles that ends in a condyle, the mandibular condyle. It is thicker than the coronoid process of the mandible and consists of two portions: the condyle and the constricted portion which supports it, the neck. Condyle The most superior part of the mandible, the condyle presents an articular surface for articulation with the articular disk of the temporomandibular joint; it is convex from before backward and from side to side, and extends farther on the posterior than on the anterior surface. Its long axis is directed medialward and slightly backward, and if prolonged to the middle line will meet that of the opposite condyle near the anterior margin of the foramen magnum. At the lateral extremity of the condyle is a small tubercle for the attachment of the temporomandibular ligament. The articular surface of the condyle is covered by fibrous tissue, and interfaces with an articu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megalomys Audreyae Molars
''Megalomys'' is a genus of rodent in the family Cricetidae, part of the tribe Oryzomyini. The genus contains five large rodents from various Caribbean islands, of which two are known to have survived into modern times, but all of which are now extinct. The last species to survive was ''M. desmarestii'' from Martinique, which became extinct after the Mount Pelée eruption in 1902. Ancient DNA analysis places ''Megalomys'' forming a clade with '' Pennatomys,'' sister to the clade containing ''Aegialomys'', ''Nesoryzomys, Melanomys'' and ''Sigmodontomys,'' having diverged from the mainland clade around 7 million years ago. It contains the following species: Recently extinct species: * ''Megalomys desmarestii'' (Martinique giant rice rat) * ''Megalomys luciae'' (Saint Lucia giant rice rat) Fossil species: *''Megalomys audreyae'' (Barbuda giant rice rat) *'' Megalomys curazensis'' (Curaçao giant rice rat) *'' Megalomys georginae'' (Barbados Barbados is an island country in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiocarbon Dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was developed in the late 1940s at the University of Chicago by Willard Libby. It is based on the fact that radiocarbon () is constantly being created in the Earth's atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of it contains begins to decrease as the undergoes radioactive decay. Measuring the amount of in a sample from a dead plant or animal, such as a piece of wood or a fragment of bone, provides information that can be used to calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biogeography
Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, isolation and habitat area.Brown University, "Biogeography." Accessed February 24, 2014. . Phytogeography is the branch of biogeography that studies the distribution of plants. Zoogeography is the branch that studies distribution of animals. Mycogeography is the branch that studies distribution of fungi, such as mushrooms. Knowledge of spatial variation in the numbers and types of organisms is as vital to us today as it was to our early human ancestors, as we adapt to heterogeneous but geographically predictable environments. Biogeography is an integrative field of inquiry that unites concepts and information from ecology, evolutionary biology, taxonomy, geology, physical geography, palaeontology, and climatology.Dansereau, Pierre. 1957 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barbados
Barbados is an island country in the Lesser Antilles of the West Indies, in the Caribbean region of the Americas, and the most easterly of the Caribbean Islands. It occupies an area of and has a population of about 287,000 (2019 estimate). Its capital and largest city is Bridgetown. Inhabited by Island Caribs, Kalinago people since the 13th century, and prior to that by other Indigenous peoples of the Americas, Amerindians, Spanish navigators took possession of Barbados in the late 15th century, claiming it for the Crown of Castile. It first appeared on a Spanish map in 1511. The Portuguese Empire claimed the island between 1532 and 1536, but abandoned it in 1620 with their only remnants being an introduction of wild boars for a good supply of meat whenever the island was visited. An Kingdom of England, English ship, the ''Olive Blossom'', arrived in Barbados on 14 May 1625; its men took possession of the island in the name of James VI and I, King James I. In 1627, the first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
