Shansiodontidae Temporal range: Triassic | |
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Mounted skeleton of Tetragonias njalilus | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Therapsida |
Clade: | † Dicynodontia |
Clade: | † Kannemeyeriiformes |
Family: | † Shansiodontidae Cox, 1965 |
Genera | |
† Rhinodicynodon |
Shansiodontidae is a family of dicynodont therapsids. [1]
Dicynodontia is an extinct clade of anomodont therapsids. Dicynodonts were herbivorous animals with a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, typically toothless beak, unique amongst synapsids. Dicynodonts first appeared during the mid-Permian, and became dominant in the Late Permian, they were devastated by the end-Permian Extinction that wiped out most other therapsids, before rebounding during the Triassic, dying out towards the end of the period. They were the most successful and diverse of the non-mammalian therapsids, with over 70 genera known, varying from rat- to elephant-sized.
Anomodontia is an extinct group of non-mammalian therapsids from the Permian and Triassic periods. By far the most speciose group are the dicynodonts, a clade of beaked, tusked herbivores. Anomodonts were very diverse during the Middle Permian, including primitive forms like Anomocephalus and Patranomodon and groups like Venyukovioidea and Dromasauria. Dicynodonts became the most successful and abundant of all herbivores in the Late Permian, filling ecological niches ranging from large browsers down to small burrowers. Few dicynodont families survived the Permian–Triassic extinction event, but one lineage (Kannemeyeriiformes) evolved into large, stocky forms that became dominant terrestrial herbivores right until the Late Triassic, when changing conditions caused them to decline.
Kannemeyeria is a genus of kannemeyeriid dicynodont that lived during the Anisian age of Middle Triassic period in what is now Africa and South America. The generic name is given in honor of Dr. Daniel Rossouw Kannemeyer, the South African fossil collector who discovered the original specimen. It is one of the first representatives of the family, and hence one of the first large herbivores of the Triassic.
Dicynodon is a genus of dicynodont therapsid that flourished during the Upper Permian period. Like all dicynodonts, it was herbivorous. This animal was toothless, except for prominent tusks, hence the name. It probably cropped vegetation with a horny beak, much like a tortoise, while the tusks may have been used for digging up roots and tubers.
Sinokannemeyeria is a genus of kannemeyeriid dicynodont that lived during the Anisian age of Middle Triassic period in what is now Shanxi, China.
Stahleckeriidae is a family of dicynodont therapsids whose fossils are known from the Triassic of North America, South America, Asia and Africa.
Biseridens is an extinct genus of anomodont therapsid, and one of the most basal anomodont genera known. Originally known from a partial skull misidentified as an 'eotitanosuchian' in 1997, another well-preserved skull was found in the Xidagou Formation, an outcropping in the Qilian Mountains of Gansu, China, in 2009 that clarified its relationships to anomodonts, such as the dicynodonts.
Dicynodontoides is a genus of small to medium-bodied, herbivorous, emydopoid dicynodonts from the Late Permian. The name Dicynodontoides references its “dicynodont-like” appearance due to the caniniform tusks featured by most members of this infraorder. Kingoria, a junior synonym, has been used more widely in the literature than the more obscure Dicynodontoides, which is similar-sounding to another distantly related genus of dicynodont, Dicynodon. Two species are recognized: D. recurvidens from South Africa, and D. nowacki from Tanzania.
Elephantosaurus is an extinct genus of dicynodont from the Middle Triassic (Ladinian) Bukobay Formation. The holotype and only known specimen, catalogued as PIN 525/25, is a fragment of the skull that includes portions of the left interorbital region and nasal bones, and suggests a very large animal with a skull at least 30 centimetres (12 in) wide. The bones of the skull roof are also unusually thick. While usually considered a member of the Stahleckeriidae, generally due to its size, it probably falls just outside the group due to its frontal bone contributing substantially to the margin of the eye socket.
Zambiasaurus is an extinct genus of non-mammalian synapsids that was discovered in the Middle Triassic (Anisian) Ntawere Formation of Zambia, southern Africa. It was a large dicynodont, reconstructed using several fossil fragments, in majority belonging to probably a juvenile Zambiasaurus subersus.
The Popo Agie Formation is a Triassic geologic formation that outcrops in western Wyoming, western Colorado, and Utah. It was deposited during the Late Triassic in fluvial (river) and lacustrine (lake) environments that existed across much of what is now the American southwest. Fragmentary fossils of prehistoric reptiles and amphibians, including pseudosuchian reptiles and temnospondyl amphibians, have been discovered in the Popo Agie Formation. Dinosaur remains are also among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.
Elph is an extinct genus of dicynodont therapsids from Russia. Four specimens have been found from the Sokolki Assemblage in European Russia, representing a fauna that dates back to the Late Permian. Elph was a small herbivore that lived alongside carnivorous akidnognathids and inostranceviids, as well as larger herbivores like Dicynodon and pareiasaurids. The type species E. borealis was named in 1999. Elph has a short snout and tusks and is closely related to Interpresosaurus and Katumbia.
Kannemeyeriiformes is a group of large-bodied Triassic dicynodonts. As a clade, Kannemeyeriiformes has been defined to include the species Kannemeyeria simocephalus and all dicynodonts more closely related to it than to the species Lystrosaurus murrayi.
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.
Eubrachiosaurus is an extinct genus of stahleckeriid dicynodont known from the Late Triassic of Wyoming, United States.
Niassodon is an extinct genus of kingoriid dicynodont therapsid known from the Late Permian of Niassa Province, northern Mozambique. It contains a single species, Niassodon mfumukasi.
The Usili Formation is a Late Permian geologic formation in Tanzania. It preserves fossils of many terrestrial vertebrates from the Permian, including temnospondyls, pareiasaurs, therapsids and the archosauromorph Aenigmastropheus.
Rastodon is an extinct genus of anomodonts. It is the oldest and most basal known genus of bidentalian dicynodonts. Uniquely among dicynodonts, its tusks curve forward. The type and only species is R. procurvidens.
Bulbasaurus is an extinct genus of dicynodont that is known from the Lopingian epoch of the Late Permian period of what is now South Africa, containing the type and only species B. phylloxyron. It was formerly considered as belonging to Tropidostoma; however, due to numerous differences from Tropidostoma in terms of skull morphology and size, it has been reclassified the earliest known member of the family Geikiidae, and the only member of the group known from the Tropidostoma Assemblage Zone. Within the Geikiidae, it has been placed close to Aulacocephalodon, although a more basal position is not implausible.
Pentasaurus is an extinct genus of dicynodont of the family Stahleckeriidae, closely related to the well known Placerias. It was found in the Lower Elliot Formation of South Africa, dated to the Norian of the Late Triassic period. The genus contains the type and only species, Pentasaurus goggai. Pentasaurus is named after the ichnogenus Pentasauropus, fossil footprints that were originally described from the lower Elliot Formation in 1970 decades before the body fossils of Pentasaurus itself were recognised. Pentasauropus footprints were likely made by dicynodonts, and in South Africa Pentasaurus itself was the likely trackmaker. The name reflects the fact that a large dicynodont was predicted to have existed in the lower Elliot Formation before any body fossils were recognised, and so Pentasaurus was named after its probable footprints. This is a reversal of the more typical occurrence where fossil footprints are named after their presumed trackmakers. The name of the species honours its collector Alfred Brown, nicknamed "Gogga", which means "bug" in Afrikaans.