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Mylagaulid
The Mylagaulidae or mylagaulids are an extinct clade of sciuromorph rodents nested within the family Aplodontiidae. They are known from the Neogene of North America and China. The oldest member is the Late Oligocene '' Trilaccogaulus montanensis'' that lived some 29 million years ago (Mya), and the youngest was ''Ceratogaulus hatcheri''—formerly in the invalid genus "''Epigaulus"'' —which was found barely into the Pliocene, some 5 Mya.Hopkins (2005) Systematics Three subfamilies are recognized. The taxonomy of '' Galbreathia'' is not resolved; it might belong in Mylagaulinae, but lacks the characteristic apomorphies. Promylagaulinae *Genus '' Crucimys'' *Genus '' Promylagaulus'' *Genus '' Trilaccogaulus'' *Genus '' Simpligaulus'' Mesogaulinae *Genus '' Mesogaulus'' - includes ''Mylagaulodon'' Mylagaulinae *Genus '' Alphagaulus'' (paraphyletic) *Genus ''Ceratogaulus'' - includes "''Epigaulus"'' *Genus '' Hesperogaulus'' *Genus ''Mylagaulus'' *Genus ''Notogaulus'' *Genus '' P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceratogaulus
Horned gophers are extinct rodents from the genus ''Ceratogaulus'', a member of the extinct fossorial rodent clade Mylagaulidae. ''Ceratogaulus'' is the only known rodent genus with horns, and is the smallest known horned mammal. ''Ceratogaulus'' lived from the late Miocene to the early Pliocene epochs, 16.3 to 5.3 million years ago. Description The horned gopher had two horns; these were large (in comparison to body size), paired, and originated from the nasal bones. Horned gophers are the smallest known horned mammals and the only known rodents ever to have had horns. They are also one of only two known horned fossorial mammals, the other being '' Peltephilus'', an extinct genus of armadillo. They were native to what is now the Great Plains of North America, mostly Nebraska. The role of the horns of ''Ceratogaulus'' is subject to much speculation. Several functions have been hypothesized (see below for a more detailed analysis) including digging, mating displays or combat, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Oligocene
The Chattian is, in the geologic timescale The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochron ..., the younger of two age (geology), ages or upper of two stage (stratigraphy), stages of the Oligocene epoch (geology), Epoch/Series (stratigraphy), Series. It spans the time between . The Chattian is preceded by the Rupelian and is followed by the Aquitanian (stage), Aquitanian (the lowest stage of the Miocene). Stratigraphic definition The Chattian was introduced by Austrian palaeontologist Theodor Fuchs in 1894. Fuchs named the stage after the Chatti, a Germanic peoples, Germanic tribe.Berry, Edward W"The Mayence Basin, a Chapter of Geologic History" ''The Scientific Monthly'', Vol. 16, No. 2, February 1923. pp. 114. Retrieved March 18, 2020. The original type locality (geology), type l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apomorph
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies homology. Examples of apomorphy are the presence of erect gait, fur, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word —coined by German entomologist Willi Hennig—is derived from the Ancient Greek words (''sún''), meaning "with, together"; (''apó''), meaning "away from"; and (''morphḗ''), meaning "shape, form". Determining ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mylagaulus
''Mylagaulus'' is an extinct genus of rodents in the family Mylagaulidae. ''Mylagaulus'' lived in the Americas during the middle to late Miocene. The genus contains the following species: *''M. cambridgensis'' *''M. cornusaulax'' Czaplewski, 2012 – Miocene, Oklahoma (United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...) *''M. elassos'' *''M. kinseyi'' *''M. sesquipedalis'' References Sciuromorpha Fossil taxa described in 1878 Prehistoric rodent genera Extinct mammals of North America Taxa named by Edward Drinker Cope {{paleo-rodent-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyletic
Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic grouping (a clade) includes a common ancestor and ''all'' of its descendants. The terms are commonly used in phylogenetics (a subfield of biology) and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of synapomorphies and symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term received currency during the debates of the 1960s and 1970s accompanying the rise of cladistics, having been coined by zoologist Willi Hennig to apply to well-known taxa like Reptilia (reptiles), which is paraphyletic with respect to birds. Reptilia contains the last common ancestor of reptiles and all descendants of that ancestor exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
