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Caatinga Vesper Mouse
The caatinga vesper mouse (''Calomys expulsus'') (also known as the caatinga laucha or rejected vesper mouse) is a rodent species in the family Cricetidae from South America. It is endemic to eastern Brazil, where it is found in open savanna (cerrado) and thorny scrub (caatinga) habitats. Its karyotype has Ploidy#Diploid, 2n = 66 and Karyotype#Fundamental number, FN = 68. It was formerly synonymized with ''Calomys callosus, C. callosus'', but the latter has 2n = 50 and FN = 66. Karyologic analysis of ''C. expulsus'' has shown that the X chromosome is large and submetacentric while the Y chromosome is either acrocentric or submetacentric. Predators include the barn owl . Sexual dimorphism in shape and size occurs; the former is present mainly before the age of 20 days. Males are smaller before age 50 days and larger thereafter, which becomes less prominent after 200 days. References Calomys Endemic fauna of Brazil Fauna of the Caatinga Mammals of Brazil Rodents of South Ame ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Wilhelm Lund
Peter Wilhelm Lund (14 June 1801 – 25 May 1880) was a Danish paleontologist, zoologist, and archeologist. He spent most of his life working and living in Brazil. He is considered the father of Brazilian paleontology as well as archaeology. He was the first to describe dozens of species of pre-historic Pleistocene megafauna, including the fabled Saber-toothed cat '' Smilodon populator''. He also made the then ground-breaking discovery that humans co-existed with the long-extinct animal species, something which possibly prompted him to terminate his scientific work. His comprehensive collections are today found at the Danish Natural History Museum in Copenhagen. Early life and education Peter Wilhelm Lund was born into a wealthy family in Copenhagen. He showed an early interest in the natural science and was working towards a career in medicine but following the death of his father, his passion for natural history prompted him instead to opt for that study at the University ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X Chromosome
The X chromosome is one of the two sex-determining chromosomes ( allosomes) in many organisms, including mammals (the other is the Y chromosome), and is found in both males and females. It is a part of the XY sex-determination system and XO sex-determination system. The X chromosome was named for its unique properties by early researchers, which resulted in the naming of its counterpart Y chromosome, for the next letter in the alphabet, following its subsequent discovery. Discovery It was first noted that the X chromosome was special in 1890 by Hermann Henking in Leipzig. Henking was studying the testicles of ''Pyrrhocoris'' and noticed that one chromosome did not take part in meiosis. Chromosomes are so named because of their ability to take up staining (''chroma'' in Greek means ''color''). Although the X chromosome could be stained just as well as the others, Henking was unsure whether it was a different class of object and consequently named it ''X element'', which later ... [...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] |
Fauna Of The Caatinga
Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is ''funga''. Flora, fauna, funga and other forms of life are collectively referred to as ''biota''. Zoologists and paleontologists use ''fauna'' to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess Shale fauna". Paleontologists sometimes refer to a sequence of faunal stages, which is a series of rocks all containing similar fossils. The study of animals of a particular region is called faunistics. Etymology ''Fauna'' comes from the name Fauna, a Roman goddess of earth and fertility, the Roman god Faunus, and the related forest spirits called Fauns. All three words are cognates of the name of the Greek god Pan, and ''panis'' is the Greek equivalent of fauna. ''Fauna'' is also the word for a book that catalogues the animals in such a manner. The term was first used by ... [...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] |
Calomys
Vesper mice are rodents belonging to a genus ''Calomys''. They are widely distributed in South America. Some species are notable as the vectors of Argentinian hemorrhagic fever and Bolivian hemorrhagic fever. The genus was originally named ''Hesperomys'', but was changed to ''Calomys'' since 1962. History ''Hesperomys'' was introduced by George Robert Waterhouse in 1839 for the American rodents with cusps arranged in two series. The name combines the Greek ἑσπερος "west" and μυς "mouse". He considered it possible that species of ''Hesperomys'' would be found in the Old World, but did not doubt that the Americas were their chief abode. He included as species ''Mus bimaculatus'' (='' Calomys laucha''), ''Mus griseo-flavus'' (='' Graomys griseoflavus''), ''Mus Darwinii'' (='' Phyllotis darwini''), ''Mus zanthopygus'' (='' Phyllotis xanthopygus''), ''Mus galapagoensis'' (='' Aegialomys galapagoensis''), ''Symidon hispidum'' (='' Sigmodon hispidus''), ''Mus leucopus'' (='' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barn Owl
The barn owl (''Tyto alba'') is the most widely distributed species of owl in the world and one of the most widespread of all species of birds, being found almost everywhere except for the polar and desert regions, Asia north of the Himalayas, most of Indonesia, and some Pacific Islands. It is also known as the common barn owl, to distinguish it from the other species in its family, Tytonidae, which forms one of the two main lineages of living owls, the other being the typical owls (''Strigidae''). There are at least three major lineages of barn owl: the western barn owl of Europe, western Asia, and Africa; the eastern barn owl of southeastern Asia and Australasia; and the American barn owl of the Americas. Some taxonomic authorities classify barn owls differently, recognising up to five separate species; and further research needs to be done to resolve the disparate taxonomies. There is considerable variation of size and colour among the approximately 28 subspecies, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrocentric
The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fibers attach to the centromere via the kinetochore. The physical role of the centromere is to act as the site of assembly of the kinetochores – a highly complex multiprotein structure that is responsible for the actual events of chromosome segregation – i.e. binding microtubules and signaling to the cell cycle machinery when all chromosomes have adopted correct attachments to the spindle, so that it is safe for cell division to proceed to completion and for cells to enter anaphase. There are, broadly speaking, two types of centromeres. "Point centromeres" bind to specific proteins that recognize particular DNA sequences with high efficiency. Any piece of DNA with the point centromere DNA sequence on it will typically form a centromere if ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Y Chromosome
The Y chromosome is one of two sex chromosomes ( allosomes) in therian mammals, including humans, and many other animals. The other is the X chromosome. Y is normally the sex-determining chromosome in many species, since it is the presence or absence of Y that determines the male or female sex of offspring produced in sexual reproduction. In mammals, the Y chromosome contains the gene SRY, which triggers male development. The DNA in the human Y chromosome is composed of about 59 million base pairs, making it similar in size to chromosome 19. The Y chromosome is passed only from father to son. With a 30% difference between humans and chimpanzees, the Y chromosome is one of the fastest-evolving parts of the human genome. The human Y chromosome carries an estimated 100–200 genes, with between 45 and 73 of these being protein-coding. All single-copy Y-linked genes are hemizygous (present on only one chromosome) except in cases of aneuploidy such as XYY syndrome or XXYY syn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submetacentric
The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fibers attach to the centromere via the kinetochore. The physical role of the centromere is to act as the site of assembly of the kinetochores – a highly complex multiprotein structure that is responsible for the actual events of chromosome segregation – i.e. binding microtubules and signaling to the cell cycle machinery when all chromosomes have adopted correct attachments to the spindle, so that it is safe for cell division to proceed to completion and for cells to enter anaphase. There are, broadly speaking, two types of centromeres. "Point centromeres" bind to specific proteins that recognize particular DNA sequences with high efficiency. Any piece of DNA with the point centromere DNA sequence on it will typically form a centromere if ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calomys Callosus
The large vesper mouse (''Calomys callosus'') is a South American rodent species of the family Cricetidae. It is found in Argentina, Bolivia, Brazil and Paraguay. Its karyotype has 2n = 50 and FN = 66. It was formerly synonymized with '' C. expulsus'', but the latter has 2n = 66 and FN = 68. It is particularly notable as the vector of Bolivian hemorrhagic fever Bolivian hemorrhagic fever (BHF), also known as black typhus or Ordog Fever, is a hemorrhagic fever and zoonotic infectious disease originating in Bolivia after infection by ''Machupo mammarenavirus''.Public Health Agency of Canada: ''Machupo Vir .... References Calomys Mammals of Argentina Mammals of Bolivia Mammals of Brazil Mammals of Paraguay Rodents of South America Mammals described in 1830 Taxa named by Johann Rudolph Rengger {{Calomys-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 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 Mouse, mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, and hamsters. Rabbits, hares, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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