Myosauridae Temporal range: | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Synapsida |
Clade: | Therapsida |
Suborder: | † Anomodontia |
Clade: | † Dicynodontia |
Clade: | † Kistecephalia |
Family: | † Myosauridae Kitching, 1968 |
Genera | |
Myosauridae is a family of dicynodont therapsids. [1]
Therapsida is a clade composing of a major group of eupelycosaurian synapsids that includes mammals and their ancestors and close relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more underneath the body, resulting in a more "standing" quadripedal posture, as opposed to the lower sprawling posture of many reptiles and amphibians.
Unaysaurus is a genus of unaysaurid sauropodomorph herbivore dinosaur. Discovered in southern Brazil, in the geopark of Paleorrota, in 1998, and announced in a press conference on Thursday, December 3, 2004, it is one of the oldest dinosaurs known. It is closely related to plateosaurid dinosaurs found in Germany, which indicates that it was relatively easy for species to spread across the giant landmass of the time, the supercontinent of Pangaea.
Venyukovia is an extinct genus of venyukovioid therapsid, a basal anomodont from the Middle Permian of Russia. The type and sole species, V. prima, is known only by a partial lower jaw with teeth. Venyukovia has often been incorrectly spelt as 'Venjukovia' in English literature. This stems from a spelling error made by Russian palaeontologist Ivan Efremov in 1940, who mistakenly replaced the 'y' with a 'j', which subsequently permeated through therapsid literature before the mistake was caught and corrected. Venyukovia is the namesake for the Venyukovioidea, a group of small Russian basal anomodonts also including the closely related Otsheria, Suminia, Parasuminia and Ulemica, although it itself is also one of the poorest known. Like other venyukovioids, it had large projecting incisor-like teeth at the front and lacked canines, although the remaining teeth are simple compared to some other venyukovioids, but may resemble those of Otsheria.
Trucidocynodon is an extinct genus of ecteniniid cynodonts from the Upper Triassic (Carnian) of Brazil. It contains a single species, Trucidocynodon riograndensis. Fossils of Trucidocynodon were discovered in outcrops of the Upper Santa Maria Formation in Paleorrota Geopark, Agudo. Trucidocynodon is one of the most completely known Triassic cynodonts, as its holotype is a nearly complete and fully articulated skeleton.
Dinanomodon is a genus of dicynodont from Late Permian (Changhsingian) of the Lystrosaurus Assemblage Zone, Katberg Formation, and Cistecephalus Assemblage Zone, Balfour Formation Beaufort Group, Karoo Basin of South Africa.
The Diictodontia were a group of herbivorous Dicynodonts from the Permian and Triassic of South Africa.
Cryptodontia is a group of dicynodont therapsids that includes the families Geikiidae, Oudenodontidae, and Rhachiocephalidae. It was first named in 1860 by English paleontologist Richard Owen. Owen intended Cryptodontia to be a family, and the name was later changed to "Cryptodontidae" to reflect this ranking. The name Cryptodontia was restored in 2009 when it was redefined as a larger clade containing several families of dicynodonts.
Venyukovioidea is an infraorder of anomodont therapsids related to dicynodonts from the Permian of Russia. They have also been known as 'Venjukovioidea', as well as by the similar names 'Venyukoviamorpha' or 'Venjukoviamorpha' in literature. This in part owes to a misspelling by Russian palaeontologist Ivan Efremov in 1940 when he mistakenly spelt Venyukovia, the namesake of the group, with a 'j' instead of a 'y', which permeated through subsequent therapsid literature before the mistake was caught and corrected. The order Ulemicia has also been coined for a similar taxonomic concept in Russian scientific literature, which notably excludes Suminia and Parasuminia.
Chainosauria is a large and speciose clade of anomodont therapsid that includes the highly diverse dicynodonts and a small number of closely related basal genera —although the total composition and taxonomic scope of Chainosauria is in flux. Chainosauria was named in 1923 to group together the dicynodonts and their close relatives, namely three small anomodont genera from South Africa that made up the now defunct group 'Dromasauria'. The name soon fell into disuse, however, as it was functionally replaced by Anomodontia. Chainosauria was later revived cladistically in 2009, preserving the association of dicynodonts and the 'dromasaurs' and has since served in effect as both a cladistic and a biogeographic counterpart to the Laurasian venyukovioids, with early chainosaurs appearing to have been a Gondwanan radiation.
Pylaecephalidae is a family of dicynodont therapsids that includes Diictodon, Robertia, and Prosictodon from the Permian of South Africa. Pylaecephalids were small burrowing dicynodonts with long tusks. The family was first named in 1934 and was redefined in 2009. Diictodontidae and Robertiidae are considered junior synonyms of Pylaecephalidae; although Pylaecephalus itself is considered a junior synonym of Diictodon, the name Pylaecephalidae predates these names and therefore takes priority.
Dicynodontoidea is an infraorder of dicynodont therapsids that includes the famous dicynodont Dicynodon, Lystrosaurus and the Triassic Kannemeyeriiformes, as well as numerous other closely related species. The name was coined by American paleontologist Everett C. Olson in 1941 as an infraorder, despite using the typical "-oidea" suffix of superfamilies, and was later redefined under a phylogenetic context in 2009 by paleontologist Christian F. Kammerer.
Therochelonia is a group of dicynodont therapsids. The group was named by British paleontologist Harry Seeley in 1894 and fell into disuse in the following century. Therochelonia was redefined as a node-based clade in 2009. It is defined as the last common ancestor of Cistecephalus microrhinus and Dicynodon lacerticeps, and all of its descendants. Below is a simplified cladogram from Kammerer et al. (2011) showing the phylogenetic placement of Therochelonia:
Bidentalia is a group of dicynodont therapsids. Bidentalia was one of the first names used to describe dicynodonts; the group was established in 1876, while the name "bidentals" dates back as far as 1845. With the increasing prominence of phylogenetics, the group was redefined as a clade in 2009. Bidentalia is now considered a stem-based taxon that includes all taxa more closely related to Aulacephalodon bainii and Dicynodon lacerticeps than Emydops arctatus.
Emydopoidea is a group of Late Permian dicynodont therapsids. It includes the small-bodied Emydops, Myosaurus, and kingoriids, and the burrowing cistecephalids.
Kistecephalia is a clade of dicynodont therapsids. The group was first named in 1894, and was reinstated as a clade in 2009. Kistecephalia is a stem-based taxon defined as all taxa more closely related to Cistecephalus microrhinus than Emydops arctatus. It includes the families Myosauridae, Kingoriidae, and Cistecephalidae and is part of the larger group Emydopoidea. Kistecephalians were small in comparison to other dicynodonts. One group of kistecephalians, the cistecephalids, are thought to have been burrowers. Below is a cladogram from Kammerer et al. (2011) showing the phylogenetic relationships of kistecephalians:
Cistecephalidae is an extinct family of dicynodont therapsids from the Late Permian of South Africa, India and Zambia. It includes the genera Cistecephalus, Cistecephaloides, and Kawingasaurus. Cistecephalids are thought to have had a fossorial or burrowing lifestyle, with adaptations such as broad skulls, strong forelimbs, and squat bodies. A similar group of dicynodonts called the pylaecephalids were also fossorial, although to a lesser extent than cistecephalids. Cistecephalids showed a high level of endemism, with each of the five known species unique to a single region.
Kingoriidae is an extinct family of dicynodont therapsids. It includes the Late Permian Niassodon, Thliptosaurus, Dicynodontoides and the Triassic Kombuisia.
Rhachiocephalidae is an extinct family of dicynodont therapsids. It includes two genera from the Late Permian of southern Africa, Rhachiocephalus and Kitchinganomodon. Rhachiocephalids were the largest dicynodonts in the Permian, although the kannemeyeriiform dicynodonts of the Late Triassic grew to larger sizes. Rhachiocephalids are also unusual in that they have long, low skulls.
Endothiodontia is a clade of dicynodont therapsids that includes the family Endothiodontidae and possibly the family Eumantellidae.
Sauroscaptor is a genus of cistecephalid dicynodont from the upper Permian of India, containing one species, S. tharavati. It is remarkable for the extreme placement of its pineal foramen, which bulges out of the posterior margin of its skull.