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Dryolestid
Dryolestidae is an extinct family of Mesozoic mammals, known from the Middle Jurassic to the Early Cretaceous of the North Hemisphere. The oldest known member, ''Anthracolestes'', is known from the Middle Jurassic Itat Formation of Western Siberia, but most other representatives are known from the Late Jurassic of North America and the Late Jurassic and Early Cretaceous of Europe. Most members are only known from isolated teeth and jaw fragments. Like many other groups of early mammals, they are thought to have been insectivores. They are generally classified in Cladotheria, meaning that they are considered to be more closely related to marsupials and placentals than to monotremes. They are placed as part of the broader Dryolestida, which also includes the (possibly paraphyletic) Paurodontidae, and also sometimes the South American-Antarctic Meridiolestida, which are often considered unrelated cladotherians. Dryolestidae taxon is not based on a phylogenetic definition, but instead ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dryolestida
Dryolestida is an extinct order of mammals, known from the Jurassic and Cretaceous. They are considered basal 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 group contains Dryolestidae and the possibly paraphyletic Paurodontidae, and some other unplaced genera, which were small insectivores, known from the Middle Jurassic to Early Cretaceous of Laurasia, primarily Europe and North America, with a single record from Asia. During the Late Jurassic in North America and from the Late Jurassic to Early Cretaceous in Europe, they were among the most diverse mammal groups. They have sometimes been placed as part of a broader group, the "Dryolestoidea", which typically includes Dryolestida and Meridiolestida, a diverse group of mammals in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meridiolestida
Meridiolestida is an extinct clade of mammals known from the Cretaceous and Cenozoic of South America and possibly Antarctica. They represented the dominant group of mammals in South America during the Late Cretaceous. Meridiolestidans were morphologically diverse, containing both small insectivores such as the "sabretooth-squirrel" ''Cronopio (mammal), Cronopio,supplementary information '' as well as the clade Mesungulatoidea/Mesungulatomorpha, which ranged in size from the shrew-sized ''Reigitherium'' to the dog-sized ''Peligrotherium.'' Mesungulatoideans had highly modified dentition with bunodont (low and rounded) teeth, and were likely herbivores/omnivores. Meridiolestidans are generally classified within Cladotheria, more c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladotheria
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''. Cladotheria incorporates a set of nested mammal clades culminating in Tribosphenida (also known as Boreosphenida), mammals with fully tribosphenic teeth such as therians and a few of their closest relatives. The clade Prototribosphenida includes "the common ancestor of '' Vincelestes'' and living therians, plus all of its descendants". Apart from tribosphenids, Prototrib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthracolestes
''Anthracolestes'' is an extinct genus of dryolestid that lived during the Bathonian stage of the Middle Jurassic epoch. Distribution ''Anthracolestes sergeii'' is known from the Itat Formation of Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders .... References {{Taxonbar, from=Q133804202 Monotypic prehistoric mammal genera Fossils of Russia Fossil taxa described in 2014 Dryolestida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Itat Formation
The Itat Formation (Russian: итатская свита) is a geologic formation in western Siberia. It was deposited in the Bajocian to Bathonian ages of the Middle Jurassic. Dinosaur remains are among the fossils that have been recovered from the formation, including the proceratosaurid '' Kileskus'', as well as fish, amphibians, mammals and many other vertebrates. The formation is noted for bearing significant coal reserves, with large open pit coal mines extracting lignite from the unit currently in operation. Lithology The lower section of the formation is around 50–130 m thick, and consists of light grey sandstones with gravel, siltstone and rare coal beds. At the Dubinino locality, the 50 m exposed section of the upper part of the formation shows an irregular rhythmic alteration of fine grained sandstone, siltstone and mudstone and coal seams typically a few tens of cm's but up to several meters thick. The deposit is located on the South Eastern margin of the West Si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paurodontidae
Paurodontidae is a family of Late Jurassic to Early Cretaceous mammals in the order Dryolestida. Remains of paurodontids have been found in the United States, Britain, Portugal, and Tanzania. The group likely represents a paraphyletic group of basal non dryolestid dryolestidans. ''Paurodon'' has been suggested to have been a specilast feeder on earthworms due to the morphology of its teeth closely resembling that of the golden mole genus ''Amblysomus ''Amblysomus'' (also narrow-headed golden mole or South African golden mole) is a genus of the golden mole family, Chrysochloridae, comprising five species of the small, insect-eating, burrowing mammals endemic to Southern Africa. All five spec ...''.A.O. Averianov and T. Martin (2015). "Ontogeny and taxonomy of Paurodon valens (Mammalia, Cladotheria) from the Upper Jurassic Morrison Formation of USA" (PDF). Proceedings of the Zoological Institute of the Russian Academy of Sciences 319 (3): 326–340. References Dryolestida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crusafontia
''Crusafontia'' is an extinct genus of mammal from the Cretaceous Camarillas, El Castellar and La Huérguina Formations of Spain. The name of the animal was given in honour of the Spanish paleontologist Miquel Crusafont Pairó. ''Crusafontia'' is estimated to have been around long, though only two 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, tear ... (an upper molar right P5) and a mandible have ever been found. In one study on Mesozoic mammal mandibles, it plots with carnivorous rather than insectivorous or herbivorous species. In 2011 a second species of ''Crusafontia'' was named, ''C. amoae'', based on two upper molar teeth from Galve. However, this was synonymised with the original species in 2021.Martin, T., Averianov, A.O., Schultz, J.A., Schwermann, A.H. and Wings, O. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laolestes
''Laolestes'' is an extinct genus of dryolestid mammal. Fossil remains are known from the Morrison Formation, in stratigraphic zones 5 and 6.,Foster, J. (2007). "Appendix." ''Jurassic West: The Dinosaurs of the Morrison Formation and Their World''. Indiana University Press. pp. 327-329. the Late Jurassic of Portugal, and Early Cretaceous Wadhurst Clay of the United Kingdom. See also * Prehistoric mammal ** List of prehistoric mammals * Paleobiota of the Morrison Formation The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is found in the western United States, which has a wide assortment of Taxon, taxa represented in its fossil record, including dinosaur fossils in North America ... References Dryolestida Late Jurassic mammals of Europe Morrison mammals Early Cretaceous mammals of Europe Tithonian genus first appearances Berriasian genera Valanginian genus extinctions Fossil taxa described in 1927 Prehistoric mammal genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypsodont
Hypsodont is a pattern of dentition characterized by with high crowns, providing extra material for wear and tear. Some examples of animals with hypsodont dentition are cows and horses; all animals that feed on gritty, fibrous material. The opposite condition is called brachydont. Evolution Since the morphology of the hypsodont tooth is suited to a more abrasive diet, hypsodonty was thought to have evolved concurrently with the spread of grasslands. Grass contains phytoliths, silica-rich granules, which wear away dental tissue more quickly. Analysis has shown, however, that the development of this morphology is out of sync with the spread and flourishing of grasslands. Instead, the ingestion of grit and soil is hypothesized to be the primary driver of hypsodonty, a hypothesis termed the grit, not grass hypothesis. Morphology Hypsodont dentition is characterized by: * high-crowned teeth * A rough, flattish occlusal surface adapted for crushing and grinding * Cementum both ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Terms Of Location
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, '' Termi ... [...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] |
Dental Alveolus
Dental alveoli (singular ''alveolus'') are sockets in the jaws in which the roots of teeth are held in the alveolar process with the periodontal ligament. The lay term for dental alveoli is tooth sockets. A joint that connects the roots of the teeth and the alveolus is called a ''gomphosis'' (plural ''gomphoses''). Alveolar bone is the bone that surrounds the roots of the teeth forming bone sockets. In mammals, tooth sockets are found in the maxilla, the premaxilla, and the mandible. Etymology 1706, "a hollow", especially "the socket of a tooth", from Latin alveolus "a tray, trough, basin; bed of a small river; small hollow or cavity", diminutive of alvus "belly, stomach, paunch, bowels; hold of a ship", from PIE root *aulo- "hole, cavity" (source also of Greek aulos "flute, tube, pipe"; Serbo-Croatian, Polish, Russian ulica "street", originally "narrow opening"; Old Church Slavonic uliji, Lithuanian aulys "beehive" (hollow trunk), Armenian yli "pregnant"). The word was extended ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
