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Trionychidae
The Trionychidae are a taxonomic family of a number of turtle genera, commonly known as softshell turtles. The family was erected by Leopold Fitzinger in 1826. Softshells include some of the world's largest freshwater turtles, though many can adapt to living in highly brackish areas. Members of this family occur in Africa, Asia, and North America, with extinct species known from Australia. Most species have traditionally been included in the genus ''Trionyx'', but the vast majority have since been moved to other genera. Among these are the North American ''Apalone'' softshells that were placed in ''Trionyx'' until 1987. Characteristics They are called "softshell" because their carapaces lack horny scutes (scales), though the spiny softshell, ''Apalone spinifera'', does have some scale-like projections, hence its name. The carapace is leathery and pliable, particularly at the sides. The central part of the carapace has a layer of solid bone beneath it, as in other turtles, but t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trionychinae
The Trionychinae are a subfamily of turtles in the family Trionychidae. Classification The subfamily has 11 extant genera: *''Amyda'' *''Apalone'' *'' Axestemys'' *'' Chitra'' *'' Dogania'' *''Drazinderetes'' *'' Gobiapalone'' *''Khunnuchelys'' *'' Murgonemys'' *'' Nilssonia'' *'' Oliveremys'' *'' Palea'' *''Palaeoamyda'' *''Pelochelys'' *''Pelodiscus'' *'' Rafetoides'' (nomen dubium) *''Rafetus'' *''Trionyx ''Trionyx'' is a genus of softshell turtles belonging to the family Trionychidae. In the past many species in the family were classified in this genus, but today '' T. triunguis'', the African or Nile softshell turtle, is the only extant softshel ...'' References {{Taxonbar, from=Q2036081 Tetrapod subfamilies Taxa named by John Edward Gray ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelochelys Cantorii
The Asian giant softshell turtle (''Pelochelys cantorii''), also known commonly as Cantor's giant softshell turtle and the frog-faced softshell turtle, is a species of freshwater turtle in the family Trionychidae. The species is native to Southeast Asia. The species is critically endangered and in the 20th century has disappeared from much of its former range. Taxonomy ''P. cantorii'' is not found in New Guinea, while the two other members of the genus ''Pelochelys'', '' P. bibroni'' and '' P. signifera'' are both restricted to New Guinea. ''P. cantorii'' is relatively unstudied, and the current species may actually be composed of several taxa. One study from 1995 showed that what was once thought to be ''P. cantorii'' in New Guinea was actually ''P. bibroni'', and the earlier studies of ''P. cantorii'' only described populations farther to the west. Description The Asian giant softshell turtle has a broad head, and small eyes close to the tip of its snout. The carapace is smoo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trionyx
''Trionyx'' is a genus of softshell turtles belonging to the family Trionychidae. In the past many species in the family were classified in this genus, but today '' T. triunguis'', the African or Nile softshell turtle, is the only extant softshell still classified as ''Trionyx''. The other species still assigned to this genus are only known from fossils. ''T. triunguis'' is a relatively large, aquatic piscivore. Species The list of species follows a 2017 review of the Trionychidae by Georgios L. Georgalis and Walter G. Joyce. * '' Trionyx triunguis'' ( Forsskål, 1775) – African or Nile softshell turtle * † '' Trionyx pliocenicus'' Fucini, 1912 – Pliocene of Tuscany (Italy) * † '' Trionyx vindobonensis'' (Peters, 1855) – Miocene of Vienna (Austria) The following species are considered valid trionychid taxa, but with uncertain phylogenetic relationships. They are only referred to ''Trionyx'' provisionally due to its historic status as a wastebasket taxon Wasteba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastomeninae
Plastomeninae is an extinct subfamily of softshell turtles that inhabited most of North America from the Cretaceous to the Eocene. Members of this subfamily are also known as plastomenines. Taxonomy and evolution They are thought to have originated in North America during or shortly before the Campanian from basal trionychids that dispersed from Asia. They reached their peak diversity from the Maastrichtian through the Paleocene, having survived the Cretaceous–Paleogene extinction event. However, they went entirely extinct by the Lutetian. The last surviving member of this subfamily is thought to have been '' Plastomenus thomasii'', which is the only known member of the subfamily to have survived past the Paleocene into the Eocene. Morphological analysis supports them being the sister taxon to the flapshell turtles (subfamily Cyclanorbinae), which still survive to the present day in parts of tropical Asia and Africa, in contrast to the exclusively North American plastomenin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apalone Spinifera
The spiny softshell turtle (''Apalone spinifera'') is a species of softshell turtle, one of the largest freshwater turtle species in North America. Both the common name, spiny softshell, and the specific name, ''spinifera'' (spine-bearing), refer to the spiny, cone-like projections on the leading edge of the carapace, which are not scutes (scales). Description The spiny softshell turtle's scientific name is very descriptive of the animal. ''Apalone'' comes from the Greek word ''apalos'', meaning soft or tender, and ''spinifera'' is of Latin origin; ''spina-'' referring to thorn or spine and ''-ifer'' meaning bearing. This species is a member of the family Trionychidae, and one of the most distinguishing features of members in this family is the presence of a leathery, moderately flexible carapace. This is caused by loss of keratinized scutes and some bony tissue loss. Spiny softshell turtles have webbed feet, each with three claws. Another distinguishing feature of softshell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apalone
''Apalone'' is a genus of turtles in the family Trionychidae. Species of ''Apalone'' are native to North America. Geographic range Most ''Apalone'' species are restricted to the United States, though the range of the spiny softshell, ''A. spinifera'', extends into southern Canada and northern Mexico. Taxonomy ''Apalone'' is a fairly new classification, resurrected by Meylan in 1987, assigned to North American species of the genus ''Trionyx''. They are still listed as ''Trionyx'' in some texts. (''Trionyx'' now refers specifically to certain softshell species found mainly in Africa.) Sexual dimorphism Turtles of the genus ''Apalone'' exhibit marked sexual dimorphism. In carapace length, females grow to about twice the size of males. In males, the claws on the front feet are longer than those on the back feet, but in females, the claws on the back feet are longer. In males, the stout tail extends well beyond the posterior edge of the carapace, but in females, the relatively thinn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclanorbinae
Cyclanorbinae, also known commonly as the flapshell turtles, is a subfamily of softshell turtles in the family Trionychidae. The subfamily is native to Africa and Asia. Taxonomy Morphological evidence supports Cyclanorbinae being the sister group to the Plastomeninae, an extinct subfamily of softshell turtles that inhabited North America from the Cretaceous to the Eocene. Genera The subfamily Cyclanorbinae contains the following three extant genera.Turtle Taxonomy Working Group (Rhodin, Anders G.J.; Parham, James F.; van Dijk, Peter Paul; Iverson, John B.) (2009"Turtles of the World: Annotated Checklist of Taxonomy and Synonymy, 2009 Update". ''Chelonian Research Monographs'' (5): 000.39-000.84. (Cyclanorbinae, pp. 000.55-000.56). *'' Cyclanorbis'' *'' Cycloderma'' *''Lissemys'' One extinct prehistoric genus is also known from fossil remains: '' Nemegtemys'' , from the Cretaceous of Mongolia. Geographic range Species In biology, a species is the basic unit of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelodiscus Sinensis
The Chinese softshell turtle (''Pelodiscus sinensis'') is a species of softshell turtle that is native to China (Inner Mongolia to Guangxi, including Hong Kong) and Taiwan, with records of escapees—some of which have established introduced populations—in a wide range of other Asian countries, as well as Spain, Brazil and Hawaii. Populations native to Northeast China, Russia, Korea and Japan were formerly included in this species, but are now regarded as separate as the northern Chinese softshell turtle (''P. maackii''). Furthermore, localized populations in Guangxi and Hunan (where the Chinese softshell turtle also is present), as well as Vietnam, are recognized as the lesser Chinese softshell turtle (''P. parviformis'') and Hunan softshell turtle (''P. axenaria''). The Chinese softshell turtle is a vulnerable species, threatened by disease, habitat loss, and collection for food such as turtle soup. Additionally, millions are now farmed, especially in China, to support t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ZW Sex-determination System
The ZW sex-determination system is a chromosomal system that determines the sex of offspring in birds, some fish and crustaceans such as the giant river prawn, some insects (including butterflies and moths), the schistosome family of flatworms, and some reptiles, e.g. majority of snakes, lacertid lizards and monitors including Komodo dragons. It is also used in some plants where it has probably evolved independently on several occasions. The letters Z and W are used to distinguish this system from the XY sex-determination system. In this system, females have a pair of dissimilar ZW chromosomes, and males have two similar ZZ chromosomes. In contrast to the XY sex-determination system and the X0 sex-determination system, where the sperm determines the sex, in the ZW system, the ovum determines the sex of the offspring. Males are the homogametic sex (ZZ), while females are the heterogametic sex (ZW). The Z chromosome is larger and has more genes, like the X chromosome in the XY sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Softshell Turtle
The Chinese softshell turtle (''Pelodiscus sinensis'') is a species of softshell turtle that is native to China (Inner Mongolia to Guangxi, including Hong Kong) and Taiwan, with records of escapees—some of which have established introduced populations—in a wide range of other Asian countries, as well as Spain, Brazil and Hawaii. Populations native to Northeast China, Russia, Korea and Japan were formerly included in this species, but are now regarded as separate as the northern Chinese softshell turtle (''P. maackii''). Furthermore, localized populations in Guangxi and Hunan (where the Chinese softshell turtle also is present), as well as Vietnam, are recognized as the lesser Chinese softshell turtle (''P. parviformis'') and Hunan softshell turtle (''P. axenaria''). The Chinese softshell turtle is a vulnerable species, threatened by disease, habitat loss, and collection for food such as turtle soup. Additionally, millions are now farmed, especially in China, to support t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microchromosome
A microchromosome (μChr) is a type of very small chromosome which is a typical component of the karyotype of birds, some reptiles, fish, and amphibians; they have yet to be found in mammals. They are less than 20 Mb in size; chromosomes which are greater than 40 Megabase, Mb in size are known as macrochromosomes (MChrs), while those between 20 and 40 Mb are classified as intermediate chromosomes. Microchromosomes are characteristically very small and often cytogenetically indistinguishable in a karyotype. While originally thought to be insignificant fragments of chromosomes, in species where they have been studied they have been found to be rich in genes and high in GC content. In chickens, microchromosomes have been estimated to contain between 50 and 75% of all genes. The presence of microchromosomes makes ordering and identifying chromosomes into a coherent karyotype particularly difficult. During metaphase, they appear merely as 0.5-1.5 μm long specks. Their small size and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turtle
Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked turtles), which differ in the way the head retracts. There are 360 living and recently extinct species of turtles, including land-dwelling tortoises and freshwater terrapins. They are found on most continents, some islands and, in the case of sea turtles, much of the ocean. Like other amniotes (reptiles, birds, and mammals) they breathe air and do not lay eggs underwater, although many species live in or around water. Turtle shells are made mostly of bone; the upper part is the domed carapace, while the underside is the flatter plastron or belly-plate. Its outer surface is covered in scales made of keratin, the material of hair, horns, and claws. The carapace bones develop from ribs that grow sideways and develop into broad flat plates th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
