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Tokudaia
''Tokudaia'' is a genus of murine rodent native to Japan. Known as Ryūkyū spiny rats or spinous country-rats, population groups exist on several non-contiguous islands. Despite differences in name and appearance, they are the closest living relatives of the Eurasian field mouse (''Apodemus''). Of the three species, both ''T. osimensis'' and ''T. tokunoshimensis'' have lost their Y chromosome and ''SRY'' gene; the sex chromosomes of ''T. muenninki'', on the other hand, are abnormally large. Named species are: * Muennink's spiny rat, ''Tokudaia muenninki'' * Ryukyu spiny rat, ''Tokudaia osimensis'' * Tokunoshima spiny rat, ''Tokudaia tokunoshimensis'' At least ''Tokudaia osimensis'' may be a cryptic species complex. See also * ''Ellobius ''Ellobius'' is a genus of rodents in the family Cricetidae. It is the only member of the tribe Ellobiusini. It contains two ('' E. lutescens'' and '' E. tancrei'') of the handful of examples of mammal species that have lost the Y chromosom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tokudaia
''Tokudaia'' is a genus of murine rodent native to Japan. Known as Ryūkyū spiny rats or spinous country-rats, population groups exist on several non-contiguous islands. Despite differences in name and appearance, they are the closest living relatives of the Eurasian field mouse (''Apodemus''). Of the three species, both ''T. osimensis'' and ''T. tokunoshimensis'' have lost their Y chromosome and ''SRY'' gene; the sex chromosomes of ''T. muenninki'', on the other hand, are abnormally large. Named species are: * Muennink's spiny rat, ''Tokudaia muenninki'' * Ryukyu spiny rat, ''Tokudaia osimensis'' * Tokunoshima spiny rat, ''Tokudaia tokunoshimensis'' At least ''Tokudaia osimensis'' may be a cryptic species complex. See also * ''Ellobius ''Ellobius'' is a genus of rodents in the family Cricetidae. It is the only member of the tribe Ellobiusini. It contains two ('' E. lutescens'' and '' E. tancrei'') of the handful of examples of mammal species that have lost the Y chromosom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tokunoshima Spiny Rat
The Tokunoshima spiny rat (''Tokudaia tokunoshimensis'') is a rodent found only on the island of Tokunoshima in the Ryukyu Islands of Japan. Due to its small habitat, it is considered endangered. It is commonly found in the secondary and primary subtropical moist broadleaf forests of this island. The karyotype has an odd diploid number, 2n = 45. Like its relative '' T. osimensis'', it is one of the few mammals that lack a Y chromosome and ''SRY'' gene. The species is threatened by deforestation and predation by feral cats and dogs. See also * ''Ellobius lutescens'' * ''Ellobius tancrei The Zaisan mole vole (''Ellobius tancrei''), or eastern mole vole, is a species of rodent in the family Cricetidae. It is found in central Asia. Description The Zaisan mole vole is highly adapted to life underground. It grows to a head and body ...'' References Tokudaia Endemic mammals of Japan Endemic fauna of the Ryukyu Islands Mammals described in 2006 {{Murinae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muennink's Spiny Rat
Muennink's spiny rat or Okinawa spiny rat (''Tokudaia muenninki'', or ) is a species of rodent in the family Muridae. Endemic to Okinawa Island, Japan, its natural habitat is subtropical moist broadleaf forest. The karyotype has 2n = 44. Its sex chromosomes are abnormally large, while the other two species in ''Tokudaia'' have lost their Y chromosome. It is found only on the northern part (Yanbaru area) of the island, above 300 m, and is thought to inhabit an area of less than 3 km2. The head and body are up to 7 inches long with a 5-inch tail. They weigh up to 7 ounces. They have a short thick body and dense fur, consisting of fine hairs and coarse, grooved spines (hence the common name “spiny rat”). The fur is brownish above and grayish white below with a faint orange tinge. The spines on the animal's back are black throughout while the spines underneath are usually white with a reddish-brown tip. The spines cover the body except for the regions around the mouth, ears, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ryukyu Spiny Rat
The Ryukyu spiny rat (''Tokudaia osimensis'') is a species of rodent in the family Muridae. Endemic to Amami Ōshima island in the Amami Islands of the Ryukyu archipelago of Japan, its natural habitat is subtropical moist broadleaf forest. The karyotype has an odd diploid number, 2n = 25. Like its relative '' T. tokunoshimensis'', it has lost its Y chromosome and ''SRY'' gene. The species is threatened by habitat destruction and fragmentation, predation by feral cats and dogs and introduced mongooses, and competition with introduced black rats. See also * ''Ellobius lutescens'' * ''Ellobius tancrei The Zaisan mole vole (''Ellobius tancrei''), or eastern mole vole, is a species of rodent in the family Cricetidae. It is found in central Asia. Description The Zaisan mole vole is highly adapted to life underground. It grows to a head and body ...'' References Y-chromosome - Will it or will it not, hold on? Rats of Asia Endemic mammals of Japan Endemic fauna o ... [...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 syndrome. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Murinae
The Old World rats and mice, part of the subfamily Murinae in the family Muridae, comprise at least 519 species. Members of this subfamily are called murines. In terms of species richness, this subfamily is larger than all mammal families except the Cricetidae and Muridae, and is larger than all mammal orders except the bats and the remainder of the rodents. Description The Murinae are native to Africa, Europe, Asia, and Australia. They are terrestrial placental mammals. They have also been introduced to all continents except Antarctica, and are serious pest animals. This is particularly true in island communities where they have contributed to the endangerment and extinction of many native animals. Two prominent murine species have become vital laboratory animals: the brown rat and house mouse are both used as medical subjects. The murines have a distinctive molar pattern that involves three rows of cusps instead of two, the primitive pattern seen most frequently in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apodemus
''Apodemus'' is a genus of Muridae (true mice and rats). The name is unrelated to that of the '' Mus'' genus, instead being derived from the Greek ἀπό-δημος (literally ''away from home''). Taxonomy Related to the Ryūkyū spiny rats (''Tokudaia'') and the prehistoric ''Rhagamys'' – and far more distantly to '' Mus'' and '' Malacomys'' – it includes these species: ''Apodemus sensu stricto'' * Striped field mouse, ''A. agrarius'' * Chevrier's field mouse, ''A. chevrieri'' * Small Japanese field mouse, ''A. argenteus'' ''Alsomys'' * South China field mouse, ''A. draco'' * Himalayan field mouse, ''A. gurkha'' * Sichuan field mouse, ''A. latronum'' * Korean field mouse, ''A. peninsulae'' * Taiwan field mouse, ''A. semotus'' * Large Japanese field mouse, ''A. speciosus'' ''Sylvaemus'' * Alpine field mouse, ''A. alpicola'' * Yellow-necked mouse, ''A. flavicollis'' – includes ''A. arianus'' * Caucasus field mouse, ''A. hyrcanicus'' * Ward's field mouse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellobius
''Ellobius'' is a genus of rodents in the family Cricetidae. It is the only member of the tribe Ellobiusini. It contains two ('' E. lutescens'' and '' E. tancrei'') of the handful of examples of mammal species that have lost the Y chromosome. The genus has the following species: * Alai mole vole (''Ellobius alaicus'') * Southern mole vole (''Ellobius fuscocapillus'') * Transcaucasian mole vole (''Ellobius lutescens'') * Northern mole vole (''Ellobius talpinus'') * Zaisan mole vole (''Ellobius tancrei'') See also *''Tokudaia ''Tokudaia'' is a genus of murine rodent native to Japan. Known as Ryūkyū spiny rats or spinous country-rats, population groups exist on several non-contiguous islands. Despite differences in name and appearance, they are the closest living rel ...'' References Rodent genera Taxa named by Gotthelf Fischer von Waldheim Taxonomy articles created by Polbot {{Arvicolinae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek grc, label=none, πλεῖστος, pleīstos, most and grc, label=none, καινός, kainós (latinized as ), 'new'. At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by the Isthmus of Panama, causing Great American Interchang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rodent
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 i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north toward the East China Sea, Philippine Sea, and Taiwan in the south. Japan is a part of the Ring of Fire, and spans Japanese archipelago, an archipelago of List of islands of Japan, 6852 islands covering ; the five main islands are Hokkaido, Honshu (the "mainland"), Shikoku, Kyushu, and Okinawa Island, Okinawa. Tokyo is the Capital of Japan, nation's capital and largest city, followed by Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe, and Kyoto. Japan is the List of countries and dependencies by population, eleventh most populous country in the world, as well as one of the List of countries and dependencies by population density, most densely populated and Urbanization by country, urbanized. About three-fourths of Geography of Japan, the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
