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Morganucodonts
Morganucodonta ("Glamorgan teeth") is an extinct order of basal Mammaliaformes, a group including crown-group mammals (Mammalia) and their close relatives. Their remains have been found in Southern Africa, Western Europe, North America, India and China. The morganucodontans were probably insectivorous and nocturnal, though like eutriconodonts some species attained large sizes and were carnivorous. Nocturnality is believed to have evolved in the earliest mammals in the Triassic (called the nocturnal bottleneck) as a specialisation that allowed them to exploit a safer, night-time niche, while most larger predators were likely to have been active during the day (though some dinosaurs, for example, were nocturnal as well). Anatomy and biology Morganucodontans had a double jaw articulation made up of the dentary-squamosal joint as well as a quadrate-articular one. This implies that they also retained one of their postdentary bones: the articular. There is a trough at the back of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. The corresponding series (stratigraphy), series of rock beds is known as the Upper Triassic. The Late Triassic is divided into the Carnian, Norian and Rhaetian Geologic time scale, ages. Many of the first dinosaurs evolved during the Late Triassic, including ''Plateosaurus'', ''Coelophysis'', ''Herrerasaurus'', and ''Eoraptor''. The Triassic–Jurassic extinction event began during this epoch and is one of the five major mass extinction events of the Earth. Etymology The Triassic was named in 1834 by Friedrich August von Namoh, Friedrich von Alberti, after a succession of three distinct rock layers (Greek meaning 'triad') that are widespread in southern Germany: the lower Buntsandstein (colourful ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crown-group
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. It is thus a way of defining a clade, a group consisting of a species and all its extant or extinct descendants. For example, Neornithes (birds) can be defined as a crown group, which includes the most recent common ancestor of all modern birds, and all of its extant or extinct descendants. The concept was developed by Willi Hennig, the formulator of phylogenetic systematics, as a way of classifying living organisms relative to their extinct relatives in his "Die Stammesgeschichte der Insekten", and the "crown" and "stem" group terminology was coined by R. P. S. Jefferies in 1979. Though formulated in the 1970s, the term was not commonly used until its reintroduction in 2000 by Graham Budd and Sören Jensen. Contents of the crown g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammaliaformes
Mammaliaformes ("mammalian forms") is a clade of synapsid tetrapods that includes the crown group mammals and their closest extinct relatives; the group radiated from earlier probainognathian cynodonts during the Late Triassic. It is defined as the clade originating from the most recent common ancestor of Morganucodonta and the crown group mammals; the latter is the clade originating with the most recent common ancestor of extant Monotremata, Marsupialia and Placentalia. Besides Morganucodonta and the crown group mammals, Mammaliaformes also includes Docodonta and ''Hadrocodium''. Mammaliaformes is a term of phylogenetic nomenclature. In contrast, the assignment of organisms to class Mammalia has traditionally been founded on traits and, on this basis, Mammalia is slightly more inclusive than Mammaliaformes. In particular, trait-based taxonomy generally includes ''Adelobasileus'' and '' Sinoconodon'' in Mammalia, though they fall outside the Mammaliaformes definition. These ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Order (biology)
Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. An immediately higher rank, superorder, is sometimes added directly above order, with suborder directly beneath order. An order can also be defined as a group of related families. What does and does not belong to each order is determined by a taxonomist, as is whether a particular order should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognized only rarely. The name of an order is usually written with a capital letter. For some groups of organisms, their orders may follow consist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teeth
A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tearing food, for defensive purposes, to intimidate other animals often including their own, or to carry prey or their young. The roots of teeth are covered by gums. Teeth are not made of bone, but rather of multiple tissues of varying density and hardness that originate from the outermost embryonic germ layer, the ectoderm. The general structure of teeth is similar across the vertebrates, although there is considerable variation in their form and position. The teeth of mammals have deep roots, and this pattern is also found in some fish, and in crocodilians. In most teleost fish, however, the teeth are attached to the outer surface of the bone, while in lizards they are attached to the inner surface of the jaw by one side. In cartilaginous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glamorgan
Glamorgan (), or sometimes Glamorganshire ( or ), was Historic counties of Wales, one of the thirteen counties of Wales that existed from 1536 until their abolishment in 1974. It is located in the South Wales, south of Wales. Originally an early medieval petty kingdom of varying boundaries known in Welsh as Kingdom of Morgannwg, Morgannwg (or Glywysing), which was then invaded and taken over by the Anglo-Normans, Normans as the Lordship of Glamorgan. The area that became known as Glamorgan was both a rural, pastoral area, and a conflict point between the Normans, Norman lords and the Welsh princes. It was defined by a large concentration of castles. After falling under English rule in the 16th century, Glamorgan became a more stable county, and exploited its natural resources to become an important part of the Industrial Revolution. Glamorgan was the most populous and industrialised county in Wales, and was once called the "crucible of the Industrial Revolution", as it contain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wareolestes
''Wareolestes rex'' ("Ware's Brigand king") is a mammaliaform from the Middle Jurassic (Bathonian) rocks of England and Scotland. It was originally known from isolated teeth from England, before a more complete jaw with teeth was found in the Kilmaluag Formation of Skye, Scotland. Etymology ''Wareolestes rex'' was named by Eric Freeman, who named it for Dr. Martin Ware "in recognition of this major contribution" to Freeman's successful work. The second part of the generic name, ''lestes'', comes from the Greek for ''brigand''. The species name ''rex'', Latin for ''king'', is both in recognition of the relatively large size of this Mesozoic mammaliaform, and a pun on the name of Mr E. J. King. Discovery ''Wareolestes rex'' was first found in and named from the Forest Marble Formation of Kirtlington, Oxfordshire, England. The holotype is a single molar tooth, originally described as a lower molar, but later argued to be an upper molar.Hahn G., Sigogneau-Russell D. and Gogefroit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinnetherium
''Dinnetherium'' is an extinct genus of mammaliaforms from the Early Jurassic of Arizona. The type species, ''D. nezorum'', was named in 1983. It was discovered in a Sinemurian layer of the Kayenta Formation, within the Gold Spring Quarry 1. The holotype is MNA V3221, which is a partial right mandible. ''Dinnetherium'' has sometimes been placed in the family Megazostrodontidae, but in 2011 the monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ... family Dinnetheriidae and order Dinnetheria were erected for the genus. Classification The phylogenetic position of ''Dinnetherium'' within mammaliaforms is shown in the cladogram below: References Morganucodonta Sinemurian life Early Jurassic synapsids of North America Jurassic Arizona Fossils of the United States ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
