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Cladotherians
Cladotheria is a clade (sometimes ranked as a legion) of mammals. It contains modern therian mammals (marsupials and placentals) and several extinct groups, such as the dryolestoids, amphitheriids and peramurids. The clade was named in 1975 by Malcolm McKenna. In 2002, it was defined as a node-based taxon containing "the common ancestor of dryolestids and living therians, plus all its descendants". A different, stem-based definition was given in 2013, in which Cladotheria contains all taxa that are closer to ''Mus musculus'' (the house mouse) than to the " symmetrodont" '' Spalacotherium tricuspidens''. Description Early cladotherians can be distinguished from other mammals by a number of derived traits (apomorphies). Their teeth differed from those of the " symmetrodonts" by the evolution of a talonid shelf ( hypoflexid) on the lower molars, which occluded with the paracone of the corresponding upper molars. A true talonid basin, allowing for the crushing and grindin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Donodontidae
Cladotheria is a clade (sometimes ranked as a legion) of mammals. It contains modern therian mammals (marsupials and placentals) and several extinct groups, such as the dryolestoids, amphitheriids and peramurids. The clade was named in 1975 by Malcolm McKenna. In 2002, it was defined as a node-based taxon containing "the common ancestor of dryolestids and living therians, plus all its descendants". A different, stem-based definition was given in 2013, in which Cladotheria contains all taxa that are closer to ''Mus musculus'' (the house mouse) than to the " symmetrodont" '' Spalacotherium tricuspidens''. Description Early cladotherians can be distinguished from other mammals by a number of derived traits (apomorphies). Their teeth differed from those of the " symmetrodonts" by the evolution of a talonid shelf ( hypoflexid) on the lower molars, which occluded with the paracone of the corresponding upper molars. A true talonid basin, allowing for the crushing and grinding of f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Jurassic
The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma (million years ago), and ends at the start of the Middle Jurassic 174.1 Ma. Certain rocks of marine origin of this age in Europe are called "Lias Group, Lias" and that name was used for the period, as well, in 19th-century geology. In southern Germany rocks of this age are called Black Jurassic. Origin of the name Lias There are two possible origins for the name Lias: the first reason is it was taken by a geologist from an England, English quarryman's dialect pronunciation of the word "layers"; secondly, sloops from north Cornwall, Cornish ports such as Bude would sail across the Bristol Channel to the Vale of Glamorgan to load up with rock from coastal limestone quarries (lias limestone from S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Legion (taxonomy)
The legion, in biological classification, is a non-obligatory taxonomic rank within the Linnaean taxonomy, Linnaean hierarchy sometimes used in zoology. Taxonomic rank In zoology, zoological Taxonomy (biology), taxonomy, the legion is: #subordinate to the class (taxonomy), class #superordinate to the cohort (taxonomy), cohort. #consists of a group of related Order (biology), orders Legions may be grouped into superlegions or subdivided into sublegions, and these again into infralegions. Use in zoology Legions and their super/sub/infra groups have been employed in some classifications of birds and mammals. Full use is made of all of these (along with cohorts and supercohorts) in, for example, Mammal classification#McKenna.2FBell classification, McKenna and Bell's classification of mammals.Malcolm McKenna, McKenna, Malcolm C. and Susan K. Bell (editors). 1997. ''Classification of Mammals Above the Species Level''. New York: Columbia University Press. See also * Linnaean taxo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symmetrodont
Symmetrodonta is a group of Mesozoic mammals and mammal-like synapsids characterized by the triangular aspect of the molars when viewed from above, and the absence of a well-developed talonid. The traditional group of 'symmetrodonts' ranges in age from the latest Triassic to the Late Cretaceous, but most research in the last 20-30 years has concluded that they are not a true taxonomic group, but include several unrelated branches of the mammal tree. Despite this, the name is still used informally by some researchers for convenience, usually restricted to the spalacotheriids and zhangheotheriids Martin, T., 2018. 6. Mesozoic mammals—early mammalian diversity and ecomorphological adaptations. In Mammalian evolution, diversity and systematics (pp. 199-300). De Gruyter.. There are some symmetrodonts with acutely-triangulated molar cusps (“acute-angled symmetrodonts”) that seem to form a true monophyletic group, and lasted from the Early Cretaceous to the Campanian, although Zha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mus Musculus
Mus or MUS may refer to: Abbreviations * MUS, the NATO country code for Mauritius * MUS, the IATA airport code for Minami Torishima Airport * MUS, abbreviation for the Centre for Modern Urban Studies on Campus The Hague, Leiden University, Netherlands * MUS, abbreviation for Medically unexplained physical symptoms * MUS, abbreviation for the Memphis University School * MUS, abbreviation for the Movimiento Unión Soberanista * MUS, abbreviation for Multiple-use water supply system, a low-cost, equitable water supply systems * Mus, abbreviation for Musca, a southern constellation * mus, ISO-639 code for the Muscogee language * Mus., abbreviation used in music degrees such as B.Mus. and M.Mus. * MUs, or million units of energy, used in India for a gigawatt hour People * Anders Mus (fl. 1501–1535), Danish civil servant in Norway * Conny Mus (1950–2010), Dutch journalist, best known as a correspondent for ''RTL Nieuws'' in Israel and the Middle East * Gus Mus (born 1944), I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stem-based Taxon
Phylogenetic nomenclature is a method of nomenclature for taxa in biology that uses phylogenetic definitions for taxon names as explained below. This contrasts with the traditional approach, in which taxon names are defined by a '' type'', which can be a specimen or a taxon of lower rank, and a description in words. Phylogenetic nomenclature is currently regulated by the '' International Code of Phylogenetic Nomenclature'' (''PhyloCode''). Definitions Phylogenetic nomenclature ties names to clades, groups consisting of an ancestor and all its descendants. These groups can equivalently be called monophyletic. There are slightly different ways of specifying the ancestor, which are discussed below. Once the ancestor is specified, the meaning of the name is fixed: the ancestor and all organisms which are its descendants are included in the named taxon. Listing all these organisms (i.e. providing a full circumscription) requires the full phylogenetic tree to be known. In practice, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Node-based Taxon
Phylogenetic nomenclature is a method of nomenclature for taxa in biology that uses phylogenetic definitions for taxon names as explained below. This contrasts with the traditional approach, in which taxon names are defined by a '' type'', which can be a specimen or a taxon of lower rank, and a description in words. Phylogenetic nomenclature is currently regulated by the '' International Code of Phylogenetic Nomenclature'' (''PhyloCode''). Definitions Phylogenetic nomenclature ties names to clades, groups consisting of an ancestor and all its descendants. These groups can equivalently be called monophyletic. There are slightly different ways of specifying the ancestor, which are discussed below. Once the ancestor is specified, the meaning of the name is fixed: the ancestor and all organisms which are its descendants are included in the named taxon. Listing all these organisms (i.e. providing a full circumscription) requires the full phylogenetic tree to be known. In practice, ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malcolm McKenna
Malcolm Carnegie McKenna (1930–2008) was an American paleontologist and author on the subject. Paleontologist McKenna began his paleontology career at the Webb School of California (grades 9-12) in Claremont, California, under noted paleontologist and teacher, Raymond Alf. He attended the California Institute of Technology and Pomona College, then graduated in paleontology at the University of California, Berkeley, where he also earned his Ph.D. He was the curator of vertebrate paleontology at the American Museum of Natural History in New York City. Through most of his four decades at the museum, he held a professorship in geosciences at Columbia University. From 1975 to 1976 he served as president of the Society of Vertebrate Paleontology. With Susan K. Bell, he co-authored the 1997 book ''Classification of Mammals Above the Species Level,'' a comprehensive work genealogy of Mammalia, including the systematics, relationships, and occurrences of all Mammal taxa, living and ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peramurid
The family Peramuridae is a family of mammals that lived in the Late Jurassic and Early Cretaceous. They are considered to be advanced cladotherians closely related to therian mammals as part of Zatheria Cladotheria is a clade (sometimes ranked as a legion) of mammals. It contains modern therian mammals (marsupials and placentals) and several extinct groups, such as the dryolestoids, amphitheriids and peramurids. The clade was named in 1975 by M .... References * Cladotheria Jurassic mammals Prehistoric mammal families Tithonian first appearances Berriasian extinctions {{cretaceous-mammal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphitheriid
Amphitheriidae is a family of Mesozoic mammals restricted to the Middle Jurassic of Britain, with indeterminate members also possibly known from the equivalently aged Itat Formation in Siberia and the Anoual Formation of Morocco. They were members of Cladotheria, more derived than members of Dryolestida, and forming a close relationship with Peramuridae.Panciroli E; Roger B.J. Benson; Richard J. Butler (2018).New partial dentaries of amphitheriid mammalian Palaeoxonodon ooliticus from Scotland, and posterior dentary morphology in early cladotherians. Acta Palaeontologica Polonica. in press. doi:10.4202/app.00434.2017. Amphitheriidae is the only family of the order Amphitheriida. Classification * Mammalia ** Yinotheria ( monotremes and relatives) ** Theriimorpha ***†Eutriconodonta ***Theriiformes ****†Allotheria *****†Gondwanatheria *****†Multituberculata **** Trechnotheria ***** † Spalacotheriidae ***** † Zhangheotheriidae ***** Cladotheria ****** † Meridiolest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dryolestoid
Dryolestida is an extinct order of mammals, primarily and possibly exclusively known from the Jurassic and Cretaceous. They are considered members of the clade Cladotheria, close to the ancestry of therian mammals. It is also believed that they developed a fully mammalian jaw and also had the three middle ear bones. Most members of the group, as with most Mesozoic mammals, are only known from fragmentary tooth and jaw remains. The taxonomic composition of the group is contested. Aside from the uncontroversial Dryolestidae and the possibly paraphyletic Paurodontidae, which were small insectivores, known from the Middle Jurassic to Early Cretaceous of Laurasia, the Meridiolestida, a diverse group of mammals including both small insectivores and mid-large sized herbivores known from the Late Cretaceous to Miocene of South America and possibly Antarctica, are also often included. However, in many phylogenetic analyses, Meridiolestida are recovered as an unrelated group of cladoth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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