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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] |
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] |
Hutchemys
''Hutchemys'' is an extinct genus of softshell turtles from the late Cretaceous (Maastrichtian stage) to the late Paleocene of New Mexico, Montana, Wyoming, Utah, and North Dakota, United States. It was first named by Walter G. Joyce, Ariel Revan, Tyler R. Lyson and Igor G. Danilov in 2009, and the type species is ''Hutchemys rememdium''. ''H. rememdium'' is known from the holotype YPM PU 16795, which consists of a nearly complete postcranial skeleton, and from the referred specimen YPM PU 16781, found in the Ekalaka Member of the Fort Union Formation, Montana. Another referred specimen, YPM PU 14985, was found in the Cedar Point Quarry, Wyoming. The second species, ''H. arctochelys'', is known from the holotype YPM PU 16319, a nearly complete carapace, and from the paratypes YPM PU 16320, YPM PU 16321, YPM PU 16322, YPM PU 16238. All specimens of ''H. arctochelys'' were recovered from the same qu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Gilmoremys
''Gilmoremys'' is an extinct genus of softshell turtle which lived during the late Cretaceous (Maastrichtian stage) of North Dakota, Montana and Wyoming, United States. Remains ''Gilmoremys'' is known from five skulls, a mandible and an incomplete postcranial skeleton. The holotype of ''G. lancensis'', USNM 6727, consists of a nearly complete carapace and an isolated hyoplastral fragment, was first assigned to the species ''Aspideretes lancensis''. Many additional specimens were later discovered including cranial remains, and the material was assigned to its own genus, ''Gilmoremys''. It was found from the Hell Creek Formation and from the Lance Formation (only the holotype). It was first named by Walter G. Joyce and Tyler R. Lyson in 2011 and the type species is ''Gilmoremys lancensis''. The generic name honors Dr. Charles W. Gilmore. A second species, ''G. gettyspherensis'', is known from the late Campanian Fruitland Formation of New Mexico. Morphology Juveniles of thi ... [...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] |
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area and 20% of its land area.Sayre, April Pulley (1999), ''Africa'', Twenty-First Century Books. . With billion people as of , it accounts for about of the world's human population. Africa's population is the youngest amongst all the continents; the median age in 2012 was 19.7, when the worldwide median age was 30.4. Despite a wide range of natural resources, Africa is the least wealthy continent per capita and second-least wealthy by total wealth, behind Oceania. Scholars have attributed this to different factors including geography, climate, tribalism, colonialism, the Cold War, neocolonialism, lack of democracy, and corruption. Despite this low concentration of wealth, recent economic expansion and the large and young population make Afr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sister Group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and taxon B are sister groups to each other. Taxa A and B, together with any other extant or extinct descendants of their most recent common ancestor (MRCA), form a monophyletic group, the clade AB. Clade AB and taxon C are also sister groups. Taxa A, B, and C, together with all other descendants of their MRCA form the clade ABC. The whole clade ABC is itself a subtree of a larger tree which offers yet more sister group relationships, both among the leaves and among larger, more deeply rooted clades. The tree structure shown connects through its root to the rest of the universal tree of life. In cladistic standards, taxa A, B, and C may represent specimens, species, genera, or any other taxonomic units. If A and B are at the same taxonomic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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