|
Dryolestidae
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 though 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. Dyolestidae is not based on a phylogenetic definition, but instead on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dryolestida
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 cladotheri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phascolestes
''Phascolestes'' is a genus of extinct mammal from the Berriasian epoch of Early Cretaceous Southern England. The type and only species is ''Phascolestes mustelulus'', which was named by Richard Owen in 1871 for dental material from the Lulworth Formation. ''Phascolestes'' is a close relative of co-existing taxon ''Achyrodon'' within the subfamily Kurtodontinae of the family Dryolestidae 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 Siber ..., with ''Kurtodon'' being a junior synonym of ''Phascolestes'' although the subfamily name is still applicable. References Dryolestida Early Cretaceous mammals of Europe Berriasian genera Prehistoric mammal genera {{cretaceous-mammal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Achyrodon
''Achyrodon'' is an extinct genus of mammal from the Berriasian epoch of Early Cretaceous southern England. The taxon was first described by Richard Owen in 1871 for teeth from the Lulworth Formation. The taxon has been considered a synonym of co-existing '' Amblotherium pusillum'', but can be distinguished by differences in the dental anatomy and an overall smaller size. ''Achyrodon'' was closely related to co-existing genus '' Phascolestes'' and the slightly younger European form '' Crusafontia'', and together they make up the subfamily Kurtodontinae within Dryolestidae, a family of early mammals between modern monotremes and theria Theria (; Greek: , wild beast) is a subclass of mammals amongst the Theriiformes. Theria includes the eutherians (including the placental mammals) and the metatherians (including the marsupials) but excludes the egg-laying monotremes. ...ns with no living descendants. References Early Cretaceous mammals of Europe Berriasia ... [...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''. 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] |
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 taxa represented in its fossil record, including dinosaur fossils in North America. It is ... References Dryolestida Late Jurassic mammals of Europe Early Cretaceous mammals of Europe Tithonian genus first appearances Berriasian genera Valanginian genus extinctions Fossil taxa described in 1927 Prehistoric mammal genera {{cretace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dryolestes
''Dryolestes'' is an extinct genus of Late Jurassic mammal from the Morrison Formation and the Alcobaça Formation The Alcobaça Formation, previously known as the Guimarota Formation and also known as the Consolação Unit, is a geological formation in Portugal. It dates back to the Kimmeridgian stage of the Late Jurassic. It is an important source of inform ... of Portugal. The type species ''Dryolestes priscus'' is present in stratigraphic zones 2, 5, and 6.Foster, J. (2007). "Appendix." ''Jurassic West: The Dinosaurs of the Morrison Formation and Their World''. Indiana University Press. pp. 327-329. See also * Prehistoric mammal ** List of prehistoric mammals * Paleobiota of the Morrison Formation References Further reading * Foster, J. (2007). Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press. 389pp. Dryolestida Kimmeridgian genus first appearances Tithonian genus extinctions Jurassic mammals of Europe Ju ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dryolestes Priscus
''Dryolestes'' is an extinct genus of Late Jurassic mammal from the Morrison Formation and the Alcobaça Formation of Portugal. The type species ''Dryolestes priscus'' is present in stratigraphic zones 2, 5, and 6.Foster, J. (2007). "Appendix." ''Jurassic West: The Dinosaurs of the Morrison Formation and Their World''. Indiana University Press. pp. 327-329. 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 taxa represented in its fossil record, including dinosaur fossils in North America. It is ... References Further reading * Foster, J. (2007). Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press. 389pp. Dryolestida Kimmeridgian genus first appearances Tithonian genus extinctions Jurassic mammals of Europe Jura ... [...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,supplementary information '' as well as the clade Mesungulatoidea/Mesungulatomorpha, which ranged in size from the shrew-sized '''' to the dog-sized '' |
Hypsodont
Hypsodont is a pattern of dentition with high-crowned teeth and enamel extending past the gum line, 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 flourishing of grasslands. Instead, the ingestion of grit and soil is hypothesized to be the primary driver of hypsodonty (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 above ... [...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 Dryolesti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Terms Of Location
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. 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 anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabularies for subdisciplines of anatom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyletic
In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic group (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 Synapomorphy and apomorphy, synapomorphies and symplesiomorphy, symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term was coined by Willi Hennig to apply to well-known taxa like Reptilia (reptiles) which, as commonly named and traditionally defined, is paraphyletic with respect to mammals and birds. Reptilia contains the last common ancestor of reptiles a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
