Dicynodontia

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Dicynodontia
Temporal range: Middle Permian to Late Triassic 268–201.4  Ma
Iziko Diictodon Hibernating Pair.JPG
Skeleton of Diictodon
Placerias.jpg
Skeleton of Placerias
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Therapsida
Suborder:† Anomodontia
Clade:† Chainosauria
Clade:† Dicynodontia
Owen, 1859
Clades & genera

see "Taxonomy"

Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivores that typically bore a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, typically toothless beak, unique amongst all synapsids. Dicynodonts first appeared in Southern Pangaea during the mid-Permian, ca. 270–260 million years ago, and became globally distributed and the dominant herbivorous animals in the Late Permian, ca. 260–252 Mya. They were devastated by the end-Permian Extinction that wiped out most other therapsids ca. 252 Mya. They rebounded during the Triassic but died out towards the end of that period. They were the most successful and diverse of the non-mammalian therapsids, with over 70 genera known, varying from rat-sized burrowers to elephant-sized browsers.

Contents

Characteristics

Dicynodont fossils Dinodontosaurus museu2x.jpg
Dicynodont fossils
Diictodon life-sized model Diictodon-A72-03.jpg
Diictodon life-sized model

The dicynodont skull is highly specialised, light but strong, with the synapsid temporal openings at the rear of the skull greatly enlarged to accommodate larger jaw muscles. The front of the skull and the lower jaw are generally narrow and, in all but a number of primitive forms, toothless. Instead, the front of the mouth is equipped with a horny beak, as in turtles and ceratopsian dinosaurs. Food was processed by the retraction of the lower jaw when the mouth closed, producing a powerful shearing action, [2] which would have enabled dicynodonts to cope with tough plant material. Dicynodonts typically had a pair of enlarged maxillary caniniform teeth, analogous to the tusks present in some living mammals. In the earliest genera, they were merely enlarged teeth, but in later forms they independently evolved into ever-growing teeth like mammal tusks multiple times. [3] In some dicynodonts, the presence of tusks has been suggested to be sexually dimorphic. [4] Some dicynodonts such as Stahleckeria lacked true tusks and instead bore tusk-like extensions on the side of the beak. [5] [6] : 139 

The body is short, strong and barrel-shaped, with strong limbs. In large genera (such as Dinodontosaurus ) the hindlimbs were held erect, but the forelimbs bent at the elbow. Both the pectoral girdle and the ilium are large and strong. The tail is short.[ citation needed ]

Pentasauropus dicynodont tracks suggest that dicynodonts had fleshy pads on their feet. [7] Mummified skin from specimens of Lystrosaurus in South Africa have numerous raised bumps. [8]

Endothermy and soft tissue anatomy

Dicynodonts have long been suspected of being warm-blooded animals. Their bones are highly vascularised and possess Haversian canals, and their bodily proportions are conducive to heat preservation. [9] In young specimens, the bones are so highly vascularised that they exhibit higher channel densities than most other therapsids. [10] Yet, studies on Late Triassic dicynodont coprolites paradoxically showcase digestive patterns more typical of animals with slow metabolisms. [11]

More recently, the discovery of hair remnants in Permian coprolites possibly vindicates the status of dicynodonts as endothermic animals. As these coprolites come from carnivorous species and digested dicynodont bones are abundant, it has been suggested that at least some of these hair remnants come from dicynodont prey. [12] A new study using chemical analysis seemed to suggest that cynodonts and dicynodonts both developed warm blood independently before the Permian extinction. [13]

History

An illustration of the skull of Dicynodon lacerticeps, first published in an 1845 description by Richard Owen Dicynodon lacerticeps.jpg
An illustration of the skull of Dicynodon lacerticeps , first published in an 1845 description by Richard Owen

A 2024 paper posited that rock art of a superficially walrus-like imaginary creature with downcurved tusks created by the San people of South Africa prior to 1835 may have been partly inspired by fossil dicynodont skulls which erode out of rocks in the area. [14]

Dicynodonts have been known to science since the mid-1800s. The South African geologist Andrew Geddes Bain gave the first description of dicynodonts in 1845. At the time, Bain was a supervisor for the construction of military roads under the Corps of Royal Engineers and had found many reptilian fossils during his surveys of South Africa. Bain described these fossils in an 1845 letter published in Transactions of the Geological Society of London , calling them "bidentals" for their two prominent tusks. [15] In that same year, the English paleontologist Richard Owen named two species of dicynodonts from South Africa: Dicynodon lacerticeps and Dicynodon bainii . Since Bain was preoccupied with the Corps of Royal Engineers, he wanted Owen to describe his fossils more extensively. Owen did not publish a description until 1876 in his Descriptive and Illustrated Catalogue of the Fossil Reptilia of South Africa in the Collection of the British Museum. [16] By this time, many more dicynodonts had been described. In 1859, another important species called Ptychognathus declivis was named from South Africa. In the same year, Owen named the group Dicynodontia. [17] In his Descriptive and Illustrated Catalogue, Owen honored Bain by erecting Bidentalia as a replacement name for his Dicynodontia. [16] The name Bidentalia quickly fell out of use in the following years, replaced by popularity of Owen's Dicynodontia. [18]

Evolutionary history

Eodicynodon, a basal dicynodont from middle Permian South Africa. Eodicynodon BW.jpg
Eodicynodon , a basal dicynodont from middle Permian South Africa.
Lisowicia bojani Wikipedia Juandertal.jpg
Lisowicia Size Comparison.svg
Lisowicia , from Late Triassic Poland

Dicynodonts first appeared during the Middle Permian in the Southern Hemisphere, with South Africa being the centre of their known diversity, and underwent a rapid evolutionary radiation, becoming globally distributed and amongst the most successful and abundant land vertebrates during the Late Permian. [19] [20] During this time, they included a large variety of ecotypes, including large, medium-sized, and small herbivores and short-limbed mole-like burrowers. [21]

Only four lineages are known to have survived the Great Dying; the first three represented with a single genus each: Myosaurus , Kombuisia , and Lystrosaurus , the latter being the most common and widespread herbivores of the Induan (earliest Triassic). None of these survived long into the Triassic. The fourth group was the Kannemeyeriiformes, the only dicynodonts who diversified during the Triassic. [22] These stocky, pig- to ox-sized animals were the most abundant herbivores worldwide from the Olenekian to the Ladinian age. By the Carnian they had been supplanted by traversodont cynodonts and rhynchosaur reptiles. During the Norian (middle of the Late Triassic), perhaps due to increasing aridity, they drastically declined, and the role of large herbivores was taken over by sauropodomorph dinosaurs.[ citation needed ]

Fossils of an Asian elephant-sized dicynodont Lisowicia bojani discovered in Poland indicate that dicynodonts survived at least until the late Norian or earliest Rhaetian (latest Triassic); this animal was also the largest known dicynodont species. [23] [24]

Six fragments of fossil bone discovered in Queensland, Australia, were interpreted as remains of a skull in 2003. This suggested to indicate that dicynodonts survived into the Cretaceous in southern Gondwana. [25] The dicynodont affinity of these specimens was questioned (including a proposal that they belonged to a baurusuchian crocodyliform by Agnolin et al. in 2010), [26] and in 2019 Knutsen and Oerlemans considered this fossil to be of Plio-Pleistocene age, and reinterpreted it as a fossil of a large mammal, probably a diprotodontid. [27]

With the decline and extinction of the kannemeyerids, there were to be no more dominant large synapsid herbivores until the middle Paleocene epoch (60 Ma) when mammals, distant descendants of cynodonts, began to diversify after the extinction of the non-avian dinosaurs.

Systematics

Taxonomy

Dicynodontia was originally named by the English paleontologist Richard Owen. It was erected as a family of the order Anomodontia and included the genera Dicynodon and Ptychognathus . Other groups of Anomodontia included Gnathodontia, which included Rhynchosaurus (now known to be an archosauromorph) and Cryptodontia, which included Oudenodon . Cryptodonts were distinguished from dicynodonts from their absence of tusks. Although it lacks tusks, Oudenodon is now classified as a dicynodont, and the name Cryptodontia is no longer used. Thomas Henry Huxley revised Owen's Dicynodontia as an order that included Dicynodon and Oudenodon. [28] Dicynodontia was later ranked as a suborder or infraorder with the larger group Anomodontia, which is classified as an order. The ranking of Dicynodontia has varied in recent studies, with Ivakhnenko (2008) considering it a suborder, Ivanchnenko (2008) considering it an infraorder, and Kurkin (2010) considering it an order. [29]

Many higher taxa, including infraorders and families, have been erected as a means of classifying the large number of dicynodont species. Cluver and King (1983) recognised several main groups within Dicynodontia, including Eodicynodontia (containing only Eodicynodon), Endothiodontia (containing only Endothiodontidae), Pristerodontia (Pristerodontidae, Cryptodontidae, Aulacephalodontidae, Dicynodontidae, Lystrosauridae, and Kannemeyeriidae), Kingoriamorpha (containing only Kingoriidae), Diictodontia (Diictodontidae, Robertiidae, Cistecephalidae, Emydopidae and Myosauridae), and Venyukoviamorpha. [30] Most of these taxa are no longer considered valid. Kammerer and Angielczyk (2009) suggested that the problematic taxonomy and nomenclature of Dicynodontia and other groups results from the large number of conflicting studies and the tendency for invalid names to be mistakenly established. [18]

Endothiodon.jpg
Endothiodon Scale V3.svg
Endothiodon
Dicynodon trigoniceps 1 DB.jpg
Pristerodon mackayi scale.svg
Pristerodon
Diictodon EF.jpg
Diictodon feliceps scale.svg
Diictodon
Cistecephalus Cistecephalus1DB.jpg
Cistecephalus
Dicynodontoides, a small dicynodont from Africa's Upper Permian KingoriaDB.jpg
Dicynodontoides , a small dicynodont from Africa's Upper Permian
Myosaurus Myosaurus.jpg
Myosaurus
Australobarbarus Australobarbarus1DB.jpg
Australobarbarus
Aulacephalodon Aulacocephalodon12DB.jpg
Aulacephalodon
Geikia (G. elginensis and G. locusticeps) Geikia sppDB24.jpg
Geikia (G. elginensis and G. locusticeps)
Pelanomodon PelanomodonDB16.jpg
Pelanomodon
Gordonia Gordonia traquairi restoration and skull (cropped).jpg
Gordonia
Lystrosaurus BW.jpg
Lystrosaurus murrayi scale.svg
Lystrosaurus murrayi
Dinodontosaurus Dinodontosaurus1DB.jpg
Dinodontosaurus
Wadiasaurus1DB.jpg
Wadiasaurus indicus scale.svg
Wadiasaurus
Woznikella Woznikella.jpg
Woznikella
Moghreberia Moghreberia.jpg
Moghreberia
Stahleckeria1DB.jpg
Stahleckeria potens scale.svg
Stahleckeria
Ufudocyclops profile 2.png
Ufudocyclops scale.svg
Ufudocyclops

Phylogeny

Below is a cladogram modified from Angielczyk et al. (2021): [31]

Dicynodontia

Current classification

South African geomyth

A horned serpent cave art is known from the La Belle France cave in South Africa, often conflated with the Dingonek. It may be based on dicynodont fossils. [32]

See also

Related Research Articles

<span class="mw-page-title-main">Therapsida</span> Clade of tetrapods including mammals

Therapsida is a clade comprising 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" quadrupedal posture, as opposed to the lower sprawling posture of many reptiles and amphibians.

<span class="mw-page-title-main">Anomodontia</span> Suborder of stem-mammals

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, finally going extinct during the Triassic–Jurassic extinction event.

<i>Cistecephalus</i> Extinct genus of dicynodonts

Cistecephalus is an extinct genus of dicynodont therapsid from the Late Permian of southern Africa. It was a small, specialised, burrowing dicynodont, possibly with habits similar to a modern mole. The head was flattened and wedge-shaped, the body long, and the forelimbs very strong, with similarities in structure to the forelimb of modern burrowing mammals.

<i>Diictodon</i> Extinct genus of dicynodonts

Diictodon is an extinct genus of pylaecephalid dicynodont that lived during the Late Permian period, approximately 255 million years ago. Fossils have been found in the Cistecephalus Assemblage Zone of the Madumabisa Mudstone of the Luangwa Basin in Zambia and the Tropidostoma Assemblage Zone of the Teekloof Formation, Tapinocephalus Assemblage Zone of the Abrahamskraal Formation, Dicynodon Assemblage Zone of the Balfour Formation, Cistecephalus Assemblage Zone of the Middleton or Balfour Formation of South Africa and the Guodikeng Formation of China. Roughly half of all Permian vertebrate specimens found in South Africa are those of Diictodon. This small herbivorous animal was one of the most successful synapsids in the Permian period.

<i>Dicynodon</i> Extinct genus of dicynodonts

Dicynodon is a genus of dicynodont therapsid that flourished during the Upper Permian period. Like all dicynodonts, it was an herbivorous animal. This synapsid 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.

<i>Emydops</i> Extinct genus of dicynodonts

Emydops is an extinct genus of dicynodont therapsids from the Middle Permian to Late Permian of what is now South Africa. The genus is generally small and herbivorous, sharing the dicynodont synapomorphy of bearing two tusks. In the following years, the genus grew to include fourteen species. Many of these species were erected on the basis of differences in the teeth and the positioning of the frontal and parietal bones. A 2008 study narrowed Emydops down to two species, E. arctatus and the newly described E. oweni.

<i>Myosaurus</i> Extinct genus of dicynodont from the lower Triassic

Myosaurus is a genus of dicynodont synapsids. Myosaurus was a small, herbivorous synapsid that existed around the early Triassic period. All of the fossils found of this species were found in Antarctica and South Africa. Compared to other fossils found from species that existed during this time, the Myosaurus is not common in the fossil record. This is due to a shortage of discovered fossils that possess characteristics unique to the Myosaurus. Notably, under 130 fossil fragments have been found that have been classified as Myosauridae, and almost all have been skulls. These skulls can be classified as Myosaurus because this species, unlike other dicynodonts, do not possess tusks or postfrontal teeth. The only species identified in the family Myosauridae is the Myosaurus gracilis, or M. gracilis. It should be recognized that the Myosaurus is almost always referred to as the M. gracilis in scientific research.

<i>Dicynodontoides</i> Extinct genus of 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.

<i>Daptocephalus</i> Extinct genus of dicynodonts

Daptocephalus is an extinct genus of dicynodont synapsid, which was found in Late Permian strata, in a biozone known precisely for the presence of fossils of this dicynodont, the Daptocephalus Assemblage Zone, in the Karoo Basin in South Africa. An additional species, D. huenei, is known from the Usili Formation in Tanzania and was formerly assigned to the genus Dicynodon before a study in 2019 recognised that the type specimen belonged to Daptocephalus.

<i>Eosimops</i> Extinct genus of dicynodonts

Eosimops is an extinct genus of pylaecephalid dicynodonts. They were small synapsids superficially resembling modern mammals. Eosimops is known from several skull specimens, as well as one complete skeleton. Eosimops lived during the Middle Permian of South Africa.

<i>Odontocyclops</i> Extinct genus of dicynodonts

Odontocyclops is an extinct genus of Dicynodonts that lived in the Late Permian. Dicynodonts are believed to be the first major assemblage of terrestrial herbivores. Fossils of Odontocyclops have been found in the Karoo Basin of South Africa and the Luangwa Valley of Zambia. The phylogenetic classification of Odontocyclops has been long under debate, but most current research places them as their own genus of Dicynodonts and being very closely related to Rhachiocephalus and Oudenodon.

<i>Aulacephalodon</i> Extinct genus of dicynodonts

Aulacephalodon is an extinct genus of medium-sized dicynodonts, or non-mammalian synapsids, that lived during late Permian period. Individuals of Aulacephalodon are commonly found in the Lower Beaufort Group of the Karoo Supergroup of South Africa. Rising to dominance during the Late Permian, Aulacephalodon was among the largest terrestrial vertebrate herbivores until its extinction at the end of the Permian. Two species have been named, the type species, A. bainii, and a second species, A. peavoti. However, debate exists among paleontologists if A. peavoti is a true member of the genus Aulacephalodon. Aulacephalodon belongs to the family Geikiidae, a family of dicynodonts generally characterized by their short, broad skulls and large nasal bosses. Sexual dimorphism has been identified in A. bainii.

<span class="mw-page-title-main">Lystrosauridae</span> Extinct family of dicynodonts

Lystrosauridae is a family of dicynodont therapsids from the Permian and Triassic time periods. It includes two genera, Lystrosaurus and Kwazulusaurus. Kwazulusaurus includes a single species, K. shakai, from the Late Permian of South Africa and Lystrosaurus includes many species from the Late Permian and Early Triassic of South Africa, India, and Antarctica.

<span class="mw-page-title-main">Venyukovioidea</span> Extinct infraorder of therapsids

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.

<span class="mw-page-title-main">Chainosauria</span> Extinct clade of therapsids

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.

Syops is an extinct genus of dicynodont therapsid. The type species S. vanhoepeni was first named in 1938 as Dicynodon vanhoepeni. Fossils of the genus have been found in the Cistecephalus Assemblage Zone in the Usili Formation of the Ruhuhu Basin, Tanzania and the Upper Madumabisa Mudstone Formation of the Luangwa Basin, Zambia. Its phylogenetic placement is somewhat uncertain, with multiple different studies finding it as either a basal geikiid, rhachiocephalid a dicynodontoid more derived than the most basal genera but less derived than Lystrosauridae, or a lystrosaurid.

<span class="mw-page-title-main">Bidentalia</span> Extinct clade of dicynodonts

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.

<i>Jimusaria</i> Extinct genus of dicynodonts

Jimusaria is an extinct genus of dicynodont therapsid from the Late Permian (Changhsingian) of China. The type species J. sinkianensis from the Guodikeng Formation in Xinjiang, was originally named as a species of Dicynodon, the first from Asia, but was given its own genus in 1963 before being sunk back into Dicynodon in 1988. The genus was resurrected in 2011 by palaeontologist Christian Kammerer in a taxonomic revision of the genus Dicynodon. Jimusaria was a mid-sized dicynodont, and was similar in appearance to the South African Dicynodon, but differed from it in features such as its narrower snout. A second species, Jimusaria monanensis was described from the Naobaogou Formation of northern China in 2023.

<i>Turfanodon</i> Extinct genus of dicynodonts

Turfanodon is an extinct genus of dicynodont therapsid from the Late Permian Sunan, Guodikeng, and Naobaogou Formations of China. The holotype of T. bogdaensis was discovered between 1963-1964 and was originally named in 1973 by A. Sun with the type species Turfanodon bogdaensis, Turfanodon was reclassified as a junior synonym of the related Dicynodon in 1988 by G. M. King. T. bogdaensis remained a species of Dicynodon for over two decades before the genus was reinstated in 2011 in a revision of the taxonomy of Dicynodon by palaeontologist Christian Kammerer. A second species from Inner Mongolia, T. jiufengensis, was named in 2021 by palaeontologist Jun Liu from a nearly complete skeleton and other referred bones. Turfanodon was a relatively large dicynodont, and similar in appearance to the related Daptocephalus from South Africa.

<i>Bulbasaurus</i> Extinct genus of dicynodonts

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 Aulacephalodon, although a more basal position is not implausible.

References

  1. ↑ Racki, Grzegorz; Lucas, Spencer G. (2018). "Timing of dicynodont extinction in light of an unusual Late Triassic Polish fauna and Cuvier's approach to extinction". Historical Biology. 32 (4): 1–11. doi:10.1080/08912963.2018.1499734. S2CID   91926999.
  2. ↑ Crompton, A. W.; Hotton, N. (1967). "Functional morphology of the masticatory apparatus of two dicynodonts (Reptilia, Therapsida)". Postilla. 109: 1–51.
  3. ↑ Whitney, M. R.; Angielczyk, K. D.; Peecook, B. R.; Sidor, C. A. (2021). "The evolution of the synapsid tusk: Insights from dicynodont therapsid tusk histology". Proceedings of the Royal Society B: Biological Sciences. 288 (1961). doi:10.1098/rspb.2021.1670. PMC   8548784 . PMID   34702071. S2CID   239890042.
  4. ↑ Angielczyk, Kenneth D.; Benoit, Julien; Rubidge, Bruce S. (February 2021). Ruta, Marcello (ed.). "A new tusked cistecephalid dicynodont (Therapsida, Anomodontia) from the upper Permian upper Madumabisa Mudstone Formation, Luangwa Basin, Zambia". Papers in Palaeontology. 7 (1): 405–446. doi:10.1002/spp2.1285. ISSN   2056-2799. S2CID   210304700.
  5. ↑ Kammerer, Christian F.; Ordoñez, Maria de los Angeles (2021-06-01). "Dicynodonts (Therapsida: Anomodontia) of South America". Journal of South American Earth Sciences. 108: 103171. Bibcode:2021JSAES.10803171K. doi:10.1016/j.jsames.2021.103171. ISSN   0895-9811. S2CID   233565963.
  6. ↑ Colbert, E. H., (1969), Evolution of the Vertebrates, John Wiley & Sons Inc (2nd ed.)
  7. ↑ Citton, Paolo; Díaz-Martínez, Ignacio; de Valais, Silvina; Cónsole-Gonella, Carlos (7 August 2018). "Triassic pentadactyl tracks from the Los Menucos Group (Río Negro province, Patagonia Argentina): possible constraints on the autopodial posture of Gondwanan trackmakers". PeerJ. 6: e5358. doi: 10.7717/peerj.5358 . PMC   6086091 . PMID   30123702.
  8. ↑ Smith, Roger M.H.; Botha, Jennifer; Viglietti, Pia A. (October 2022). "Taphonomy of drought afflicted tetrapods in the Early Triassic Karoo Basin, South Africa". Palaeogeography, Palaeoclimatology, Palaeoecology. 604: 111207. Bibcode:2022PPP...60411207S. doi:10.1016/j.palaeo.2022.111207. S2CID   251781291.
  9. ↑ Bakker, Robert T. (April 1975). "Dinosaur renaissance". Scientific American. 232 (4): 58–79. Bibcode:1975SciAm.232d..58B. doi:10.1038/scientificamerican0475-58.
  10. ↑ Botha-Brink, Jennifer; Angielczyk, Kenneth D. (2010). "Do extraordinarily high growth rates in Permo-Triassic dicynodonts (Therapsida, Anomodontia) explain their success before and after the end-Permian extinction?". Zoological Journal of the Linnean Society. 160 (2): 341–365. doi: 10.1111/j.1096-3642.2009.00601.x .
  11. ↑ Bajdek, Piotr; Owocki, Krzysztof; Niedźwiedzki, Grzegorz (2014). "Putative dicynodont coprolites from the Upper Triassic of Poland". Palaeogeography, Palaeoclimatology, Palaeoecology. 411: 1–17. Bibcode:2014PPP...411....1B. doi:10.1016/j.palaeo.2014.06.013.
  12. ↑ Bajdek, Piotr; Qvarnström, Martin; Owocki, Krzysztof; Sulej, Tomasz; Sennikov, Andrey G.; Golubev, Valeriy K.; Niedźwiedzki, Grzegorz (2016). "Microbiota and food residues including possible evidence of pre-mammalian hair in Upper Permian coprolites from Russia". Lethaia. 49 (4): 455–477. doi:10.1111/let.12156.
  13. ↑ Rey, Kévin; Amiot, Romain; Fourel, François; Abdala, Fernando; Fluteau, Frédéric; Jalil, Nour-Eddine; Liu, Jun; Rubidge, Bruce S.; Smith, Roger MH; Steyer, J. Sébastien; Viglietti, Pia A; Wang, Xu; Lécuyer, Christophe (2017). "Oxygen isotopes suggest elevated thermometabolism within multiple Permo-Triassic therapsid clades". eLife. 6: e28589. doi: 10.7554/eLife.28589 . PMC   5515572 . PMID   28716184.
  14. ↑ Benoit, J (2024). "A possible later stone age painting of a dicynodont (Synapsida) from the South African Karoo". PLOS One.
  15. ↑ Bain, A.G. (1845). "On the discovery of fossil remains of bidental and other reptiles in South Africa". Transactions of the Geological Society of London. 1: 53–59. doi:10.1144/GSL.JGS.1845.001.01.72. hdl:2027/uc1.c034667778. S2CID   128602890.
  16. 1 2 Owen, R. (1876). Descriptive and Illustrated Catalogue of the Fossil Reptilia of South Africa in the Collection of the British Museum. London: British Museum. p. 88.
  17. ↑ Owen, R. (1860). "On the orders of fossil and recent Reptilia, and their distribution in time". Report of the Twenty-Ninth Meeting of the British Association for the Advancement of Science. 1859: 153–166.
  18. 1 2 Kammerer, C.F.; Angielczyk, K.D. (2009). "A proposed higher taxonomy of anomodont therapsids" (PDF). Zootaxa. 2018: 1–24.
  19. ↑ Kurkin, A. A. (July 2011). "Permian anomodonts: Paleobiogeography and distribution of the group". Paleontological Journal. 45 (4): 432–444. doi:10.1134/S0031030111030075. ISSN   0031-0301. S2CID   129331000.
  20. ↑ Olroyd, Savannah L.; Sidor, Christian A. (August 2017). "A review of the Guadalupian (middle Permian) global tetrapod fossil record". Earth-Science Reviews. 171: 583–597. Bibcode:2017ESRv..171..583O. doi: 10.1016/j.earscirev.2017.07.001 . ISSN   0012-8252.
  21. ↑ Angielczyk, Kenneth D.; Kammerer, Christian F. (2018). "5. Non-Mammalian synapsids: The deep roots of the mammalian family tree". Mammalian Evolution, Diversity and Systematics. pp. 117–198. doi:10.1515/9783110341553-005. ISBN   9783110341553. S2CID   92370138.
  22. ↑ Kammerer, Christian F.; Fröbisch, Jörg; Angielczyk, Kenneth D. (31 May 2013). "On the validity and phylogenetic position of Eubrachiosaurus browni, a kannemeyeriiform dicynodont (Anomodontia) from Triassic North America". PLOS ONE. 8 (5): e64203. Bibcode:2013PLoSO...864203K. doi: 10.1371/journal.pone.0064203 . PMC   3669350 . PMID   23741307.
  23. ↑ Tomasz Sulej; Grzegorz Niedźwiedzki (2019). "An elephant-sized Late Triassic synapsid with erect limbs". Science. 363 (6422): 78–80. Bibcode:2019Sci...363...78S. doi: 10.1126/science.aal4853 . PMID   30467179.
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  25. ↑ Thulborn, T.; Turner, S. (2003). "The last dicynodont: an Australian Cretaceous relict". Proceedings of the Royal Society B: Biological Sciences. 270 (1518): 985–993. doi:10.1098/rspb.2002.2296. JSTOR   3558635. PMC   1691326 . PMID   12803915.
  26. ↑ Agnolin, F. L.; Ezcurra, M. D.; Pais, D. F.; Salisbury, S. W. (2010). "A reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: Evidence for their Gondwanan affinities" (PDF). Journal of Systematic Palaeontology. 8 (2): 257–300. doi:10.1080/14772011003594870. S2CID   130568551.
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  28. ↑ Osborn, H.F. (1904). "Reclassification of the Reptilia". The American Naturalist. 38 (446): 93–115. doi:10.1086/278383. S2CID   84492986.
  29. ↑ Kurkin, A.A. (2010). "Late Permian dicynodonts of Eastern Europe". Paleontological Journal. 44 (6): 72–80. doi:10.1134/S0031030110060092. S2CID   131459807.
  30. ↑ Cluver, M.A.; King, G.M. (1983). "A reassessment of the relationships of Permian Dicynodontia (Reptilia, Therapsida) and a new classification of dicynodont". Annals of the South African Museum. 91: 195–273.
  31. ↑ Angielczyk, K. D.; Liu, J.; Yang, W. (2021). "A Redescription of Kunpania scopulusa, a Bidentalian Dicynodont (Therapsida, Anomodontia) from the ?Guadalupian of Northwestern China". Journal of Vertebrate Paleontology. 41 (1): e1922428. Bibcode:2021JVPal..41E2428A. doi:10.1080/02724634.2021.1922428. S2CID   236406006.
  32. ↑ Benoit J (2024) A possible later stone age painting of a dicynodont (Synapsida) from the South African Karoo. PLoS ONE 19(9): e0309908. https://doi.org/10.1371/journal.pone.0309908

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