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Bristle-spined Rat
The bristle-spined rat (''Chaetomys subspinosus'') is an arboreal rodent from the Atlantic forest in eastern Brazil. Also known as the bristle-spined porcupine or thin-spined porcupine, it is the only member of the genus ''Chaetomys'' and the subfamily Chaetomyinae. It was officially described in 1818, but rarely sighted since, until December 1986, when two specimens - one a pregnant female - were found in the vicinity of Valencia in Bahia. Since then it has been recorded at several localities in eastern Brazil, from Sergipe to Espírito Santo (there are no recent records from Rio de Janeiro), but it remains rare and threatened due to habitat loss, poaching and roadkills. Characteristics Bristle-spined rats are named because the spines on the back are more bristle-like in texture than the spines on the rest of the body. They have long, naked tails which are not prehensile. Adult animals weigh around . Their skulls are unusual in several ways. The eye socket is almost com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oldfield Thomas
Michael Rogers Oldfield Thomas (21 February 1858 – 16 June 1929) was a British zoologist. Career Thomas worked at the Natural History Museum on mammals, describing about 2,000 new species and subspecies for the first time. He was appointed to the museum secretary's office in 1876, transferring to the zoological department in 1878. In 1891, Thomas married Mary Kane, daughter of Sir Andrew Clark, heiress to a small fortune, which gave him the finances to hire mammal collectors and present their specimens to the museum. He also did field work himself in Western Europe and South America. His wife shared his interest in natural history, and accompanied him on collecting trips. In 1896, when William Henry Flower took control of the department, he hired Richard Lydekker Richard Lydekker (; 25 July 1849 – 16 April 1915) was an English naturalist, geologist and writer of numerous books on natural history. Biography Richard Lydekker was born at Tavistock Square in London. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echimyidae
Echimyidae is the family of neotropical spiny rats and their fossil relatives. This is the most species-rich family of hystricognath rodents. It is probably also the most ecologically diverse, with members ranging from fully arboreal to terrestrial to fossorial to semiaquatic habits. They presently exist mainly in South America; three members of the family also range into Central America, and the hutias are found in the Greater Antilles in the Caribbean. Species of the extinct subfamily Heteropsomyinae formerly lived on Cuba, Hispaniola, and Puerto Rico in the Antilles, probably until the arrival of Europeans. Characteristics In general form, most spiny rats resemble rats, although they are more closely related to guinea pigs and chinchillas. Most species have stiff, pointed hairs, or spines, that presumably serve for protection from predators. Many echimyids can break off their tails when attacked. This action may confuse predators long enough for the spiny rat to es ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemic Fauna Of Brazil
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can be also be referred to as an ''endemism'' or in scientific literature as an ''endemite''. For example '' Cytisus aeolicus'' is an endemite of the Italian flora. '' Adzharia renschi'' was once believed to be an endemite of the Caucasus, but it was later discovered to be a non-indigenous species from South America belonging to a different genus. The extreme opposite of an endemic species is one with a cosmopolitan distribution, having a global or widespread range. A rare alternative term for a species that is endemic is "precinctive", which applies to s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals Of Brazil
Brazil has the largest mammal diversity in the world, with more than 600 described species and more likely to be discovered. According to the International Union for Conservation of Nature, 66 of these species are endangered, and 40% of the threatened taxa belong to the primate group. 658 species are listed. The following tags are used to highlight each species' conservation status as assessed by the International Union for Conservation of Nature: Some species were assessed using an earlier set of criteria. Species assessed using this system have the following instead of near threatened and least concern categories: Infraclass: Metatheria Order: Didelphimorphia * Family: Caluromyidae ** Genus: '' Caluromys'' *** Brown-eared woolly opossum, ''C. lanatus'' LC *** Bare-tailed woolly opossum, ''C. philander'' LC * Family: Didelphidae ** Genus: ''Caluromysiops'' *** Black-shouldered opossum, ''Caluromysiops irrupta'' LC ** Genus: ''Glironia'' *** Bushy-tailed opossum, ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rodents Of South America
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are native to all major land masses except for New Zealand, 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/richochetal (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 mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, and hamsters. Rabbits, hares, and pikas, whose incisors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pymatuning Laboratory Of Ecology
The Pymatuning Laboratory of Ecology (PLE) is a year-round ecology field station of the University of Pittsburgh Department of Biological Sciences located in Linesville and South Shenango Township on the shores Pymatuning Lake in Pennsylvania. The station contains research facilities and equipment, conducts undergraduate education and courses, and serves as center for conferences, symposia, and retreats. The Pyatuning Laboratory hosts researchers from the University of Pittsburgh as well as those from universities throughout the nation and world, which have included, among others, researchers form Duke University, the University of Virginia, the University of Georgia, the University of Miami. Likewise, course instructors at the lab come from the University of Pittsburgh, but also have included instructors from other institutions including Georgia Tech, the University of Connecticut, and the National Aviary. In addition, the University of Pittsburgh has instituted a collaborative p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karyology
A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is discerned by determining the chromosome complement of an individual, including the number of chromosomes and any abnormalities. A karyogram or idiogram is a graphical depiction of a karyotype, wherein chromosomes are organized in pairs, ordered by size and position of centromere for chromosomes of the same size. Karyotyping generally combines light microscopy and photography, and results in a photomicrographic (or simply micrographic) karyogram. In contrast, a schematic karyogram is a designed graphic representation of a karyotype. In schematic karyograms, just one of the sister chromatids of each chromosome is generally shown for brevity, and in reality they are generally so close together that they look as one on photomicrographs as well u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome B
Cytochrome b within both molecular and cell biology, is a protein found in the mitochondria of eukaryotic cells. It functions as part of the electron transport chain and is the main subunit of transmembrane cytochrome bc1 and b6f complexes. Function In the mitochondrion of eukaryotes and in aerobic prokaryotes, cytochrome b is a component of respiratory chain complex III () — also known as the bc1 complex or ubiquinol-cytochrome c reductase. In plant chloroplasts and cyanobacteria, there is an analogous protein, cytochrome b6, a component of the plastoquinone-plastocyanin reductase (), also known as the b6f complex. These complexes are involved in electron transport, the pumping of protons to create a proton-motive force ( PMF). This proton gradient is used for the generation of ATP. These complexes play a vital role in cells. Structure Cytochrome b/b6 is an integral membrane protein of approximately 400 amino acid residues that probably has 8 transmembrane segments. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial
A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'' was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase coined by Philip Siekevitz in a 1957 article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). A large number of unicellular organisms, such as microsporidia, parabasalids and diplomonads, have reduced or transformed their mitochondria into other structures. One eukaryote, ''Monocercomonoides'', is known to have completely lost its mitochondria, and one multicellular organism, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogeny
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. All life on Earth is part of a single phylogenetic tree, indicating common ancestry. In a ''rooted'' phylogenetic tree, each node with descendants represents the inferred most recent common ancestor of those descendants, and the edge lengths in some trees may be interpreted as time estimates. Each node is called a taxonomic unit. Internal nodes are generally called hypothetical taxonomic units, as they cannot be directly observed. Trees are useful in fields of biology such as bioinformatics, systematics, and phylogenetics. ''Unrooted'' trees illustrate only the relatedness of the leaf nodes and do not require the ancestral root to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tooth Enamel
Tooth enamel is one of the four major Tissue (biology), tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the Crown (tooth), crown. The other major tissues are dentin, cementum, and Pulp (tooth), dental pulp. It is a very hard, white to off-white, highly mineralised substance that acts as a barrier to protect the tooth but can become susceptible to degradation, especially by acids from food and drink. Calcium hardens the tooth enamel. In rare circumstances enamel fails to form, leaving the underlying dentin exposed on the surface. Features Enamel is the hardest substance in the human body and contains the highest percentage of minerals (at 96%),Ross ''et al.'', p. 485 with water and organic material composing the rest.Ten Cate's Oral Histology, Nancy, Elsevier, pp. 70–94 The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. Enamel is formed o ... [...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 have none. Structure Adult humans normally have eight incisors, two of each type. The types of incisor 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. Typically, the mandibular central incisors erupt first, followed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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