Dicynodontia

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'''Dicynodontia''' is an extinct [[clade]] of [[anomodont]]s, an extinct type of non-mammalian [[therapsid]]. Dicynodonts were [[herbivore]]s 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 [[synapsid]]s. Dicynodonts first appeared in Southern Pangaea during the [[Guadalupian|mid-Permian]], ca. 270–260 million years ago, and became globally distributed and the dominant herbivorous animals in the [[Permian|Late Permian]], ca. 260–252 Mya. They were devastated by the [[Permian–Triassic extinction event|end-Permian mass extinction]] that wiped out most other therapsids ca. 252 Mya. They rebounded at beginning of the following [[Triassic]], but subsequently declined during the [[Late Triassic]] and died out towards the end of that period. They were the most successful and diverse of the non-mammalian therapsids, with over 80–90 [[genus|genera]] known, varying from rat-sized [[Fossorial|burrowers]] to elephant-sized [[Browsing (herbivory)|browsers]].

'''Dicynodontia''' is an extinct [[clade]] of [[anomodont]]s, an extinct type of non-mammalian [[therapsid]]. Dicynodonts were [[herbivore]]s 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 [[synapsid]]s. Dicynodonts first appeared in Southern Pangaea during the [[Guadalupian|mid-Permian]], ca. 270–260 million years ago, and became globally distributed and the dominant herbivorous animals in the [[Permian|Late Permian]], ca. 260–252 Mya. They were devastated by the [[Permian–Triassic extinction event|end-Permian mass extinction]] that wiped out most other therapsids ca. 252 Mya. They rebounded at beginning of the following [[Triassic]], but subsequently declined during the [[Late Triassic]] and died out towards the end of that period. They were the most successful and diverse of the non-mammalian therapsids, with over 80–90 [[genus|genera]] known, varying from rat-sized [[Fossorial|burrowers]] to elephant-sized [[megaherbivores]].

==Characteristics==

==Characteristics==

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 (bone)|ilium]] are large and strong. The tail is short.{{Citation needed|date=July 2021}}

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 (bone)|ilium]] are large and strong. The tail is short.{{Citation needed|date=July 2021}}

Dicynodonts vary enormously in size. The smallest were rat-sized, a size common amongst Permian members of the group, while Triassic members of the group were typically much larger,{{Cite journal |last=King |first=Gillian M. |date=1993-06 |title=Species longevity and generic diversity in dicynodont mammal-like reptiles |url=https://linkinghub.elsevier.com/retrieve/pii/003101829390074S |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=102 |issue=3-4 |pages=321–332 |doi=10.1016/0031-0182(93)90074-S}} with the youngest known member ''[[Lisowicia]]'' being around the size of an elephant, with a body mass of around {{Convert|5880|kg|lb}}.{{Cite journal |last=Romano |first=Marco |last2=Manucci |first2=Fabio |date=2021-04-03 |title=Resizing Lisowicia bojani : volumetric body mass estimate and 3D reconstruction of the giant Late Triassic dicynodont |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2019.1631819 |journal=Historical Biology |language=en |volume=33 |issue=4 |pages=474–479 |doi=10.1080/08912963.2019.1631819 |issn=0891-2963}}

===Soft tissue anatomy===

===Soft tissue anatomy===

Dicynodonts first appeared during the [[Guadalupian|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 [[Lopingian|Late Permian]].{{Cite journal|last=Kurkin|first=A. A.|date=July 2011|title=Permian anomodonts: Paleobiogeography and distribution of the group|url=http://link.springer.com/10.1134/S0031030111030075|journal=Paleontological Journal|language=en|volume=45|issue=4|pages=432–444|doi=10.1134/S0031030111030075|bibcode=2011PalJ...45..432K |s2cid=129331000|issn=0031-0301|url-access=subscription}}{{Cite journal|last1=Olroyd|first1=Savannah L.|last2=Sidor|first2=Christian A.|date=August 2017|title=A review of the Guadalupian (middle Permian) global tetrapod fossil record|journal=Earth-Science Reviews|volume=171|pages=583–597|doi=10.1016/j.earscirev.2017.07.001|bibcode=2017ESRv..171..583O|issn=0012-8252|doi-access=free}} During this time, they included a large variety of ecotypes, including large, medium-sized, and small herbivores and short-limbed mole-like burrowers.{{cite book|doi=10.1515/9783110341553-005|chapter=5. Non-Mammalian synapsids: The deep roots of the mammalian family tree |title=Mammalian Evolution, Diversity and Systematics |year=2018 |last1=Angielczyk |first1=Kenneth D. |last2=Kammerer |first2=Christian F. |pages=117–198 |isbn=978-3-11-034155-3 |s2cid=92370138 }}

Dicynodonts first appeared during the [[Guadalupian|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 [[Lopingian|Late Permian]].{{Cite journal|last=Kurkin|first=A. A.|date=July 2011|title=Permian anomodonts: Paleobiogeography and distribution of the group|url=http://link.springer.com/10.1134/S0031030111030075|journal=Paleontological Journal|language=en|volume=45|issue=4|pages=432–444|doi=10.1134/S0031030111030075|bibcode=2011PalJ...45..432K |s2cid=129331000|issn=0031-0301|url-access=subscription}}{{Cite journal|last1=Olroyd|first1=Savannah L.|last2=Sidor|first2=Christian A.|date=August 2017|title=A review of the Guadalupian (middle Permian) global tetrapod fossil record|journal=Earth-Science Reviews|volume=171|pages=583–597|doi=10.1016/j.earscirev.2017.07.001|bibcode=2017ESRv..171..583O|issn=0012-8252|doi-access=free}} During this time, they included a large variety of ecotypes, including large, medium-sized, and small herbivores and short-limbed mole-like burrowers.{{cite book|doi=10.1515/9783110341553-005|chapter=5. Non-Mammalian synapsids: The deep roots of the mammalian family tree |title=Mammalian Evolution, Diversity and Systematics |year=2018 |last1=Angielczyk |first1=Kenneth D. |last2=Kammerer |first2=Christian F. |pages=117–198 |isbn=978-3-11-034155-3 |s2cid=92370138 }}

Only four lineages are known to have survived the [[Permian–Triassic extinction event|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.{{cite journal|title=On the validity and phylogenetic position of ''Eubrachiosaurus browni'', a kannemeyeriiform dicynodont (Anomodontia) from Triassic North America |first1=Christian F.|last1=Kammerer|first2=Jörg|last2=Fröbisch|first3=Kenneth D.|last3=Angielczyk|date=31 May 2013|journal=PLOS ONE |volume=8 |issue=5 |article-number=e64203 |doi=10.1371/journal.pone.0064203|pmid=23741307|pmc=3669350|bibcode=2013PLoSO...864203K|doi-access=free}} These stocky, pig- to ox-sized animals were successful herbivores worldwide for much of the Triassic period. However during the late Triassic during the [[Norian]] and possibly the [[Carnian]], they declined, though the nature and timing of this decline is not well agreed upon.{{Cite journal |last=Racki |first=Grzegorz |last2=Lucas |first2=Spencer G. |date=2020-04-20 |title=Timing of dicynodont extinction in light of an unusual Late Triassic Polish fauna and Cuvier’s approach to extinction |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2018.1499734 |journal=Historical Biology |language=en |volume=32 |issue=4 |pages=452–461 |doi=10.1080/08912963.2018.1499734 |issn=0891-2963}} 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, at earliest 211 million years ago,{{Cite journal |last1=Kowal-Linka |first1=Monika |last2=Krzemińska |first2=Ewa |last3=Czupyt |first3=Zbigniew |date=January 2019 |title=The youngest detrital zircons from the Upper Triassic Lipie Śląskie (Lisowice) continental deposits (Poland): Implications for the maximum depositional age of the Lisowice bone-bearing horizon |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018218307545 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=514 |pages=487–501 |doi=10.1016/j.palaeo.2018.11.012|bibcode=2019PPP...514..487K |url-access=subscription }} and probably no later than around 205 million years ago{{Cite journal |last1=Mujal |first1=Eudald |last2=Sues |first2=Hans-Dieter |last3=Moreno |first3=Raphael |last4=Schaeffer |first4=Joep |last5=Sobral |first5=Gabriela |last6=Chakravorti |first6=Sanjukta |last7=Spiekman |first7=Stephan N.F. |last8=Schoch |first8=Rainer R. |date=May 2025 |title=Triassic terrestrial tetrapod faunas of the Central European Basin, their stratigraphical distribution, and their palaeoenvironments |journal=Earth-Science Reviews |language=en |volume=264 |article-number=105085 |doi=10.1016/j.earscirev.2025.105085|doi-access=free |bibcode=2025ESRv..26405085M }}); this animal was also the largest known dicynodont species.{{cite journal |author1=Tomasz Sulej |author2=Grzegorz Niedźwiedzki |year=2019 |title=An elephant-sized Late Triassic synapsid with erect limbs |journal=Science |volume=363 |issue= 6422|pages= 78–80|doi=10.1126/science.aal4853 |pmid=30467179 |bibcode=2019Sci...363...78S |doi-access=free |url=https://zenodo.org/record/2532919 }}{{cite news |last=St. Fleur |first=Nicholas |title=An Elephant-Size Relative of Mammals That Grazed Alongside Dinosaurs |url=https://www.nytimes.com/2019/01/04/science/dicynodonts-fossils-poland.html |date=4 January 2019 |work=[[The New York Times]] |access-date=6 January 2019 }}

Only four lineages are known to have survived the [[Permian–Triassic extinction event|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.{{cite journal|title=On the validity and phylogenetic position of ''Eubrachiosaurus browni'', a kannemeyeriiform dicynodont (Anomodontia) from Triassic North America |first1=Christian F.|last1=Kammerer|first2=Jörg|last2=Fröbisch|first3=Kenneth D.|last3=Angielczyk|date=31 May 2013|journal=PLOS ONE |volume=8 |issue=5 |article-number=e64203 |doi=10.1371/journal.pone.0064203|pmid=23741307|pmc=3669350|bibcode=2013PLoSO...864203K|doi-access=free}} These stocky, pig- to ox-sized animals were successful herbivores worldwide for much of the Triassic period. However during the late Triassic during the [[Norian]] and possibly the [[Carnian]], they declined, though the nature and timing of this decline is not well agreed upon. Suggested influencing factors include the [[Carnian pluvial episode]].{{Cite journal |last=Racki |first=Grzegorz |last2=Lucas |first2=Spencer G. |date=2020-04-20 |title=Timing of dicynodont extinction in light of an unusual Late Triassic Polish fauna and Cuvier’s approach to extinction |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2018.1499734 |journal=Historical Biology |language=en |volume=32 |issue=4 |pages=452–461 |doi=10.1080/08912963.2018.1499734 |issn=0891-2963}} 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, at earliest 211 million years ago,{{Cite journal |last1=Kowal-Linka |first1=Monika |last2=Krzemińska |first2=Ewa |last3=Czupyt |first3=Zbigniew |date=January 2019 |title=The youngest detrital zircons from the Upper Triassic Lipie Śląskie (Lisowice) continental deposits (Poland): Implications for the maximum depositional age of the Lisowice bone-bearing horizon |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018218307545 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=514 |pages=487–501 |doi=10.1016/j.palaeo.2018.11.012|bibcode=2019PPP...514..487K |url-access=subscription }} and probably no later than around 205 million years ago{{Cite journal |last1=Mujal |first1=Eudald |last2=Sues |first2=Hans-Dieter |last3=Moreno |first3=Raphael |last4=Schaeffer |first4=Joep |last5=Sobral |first5=Gabriela |last6=Chakravorti |first6=Sanjukta |last7=Spiekman |first7=Stephan N.F. |last8=Schoch |first8=Rainer R. |date=May 2025 |title=Triassic terrestrial tetrapod faunas of the Central European Basin, their stratigraphical distribution, and their palaeoenvironments |journal=Earth-Science Reviews |language=en |volume=264 |article-number=105085 |doi=10.1016/j.earscirev.2025.105085|doi-access=free |bibcode=2025ESRv..26405085M }}); this animal was also the largest known dicynodont species.{{cite journal |author1=Tomasz Sulej |author2=Grzegorz Niedźwiedzki |year=2019 |title=An elephant-sized Late Triassic synapsid with erect limbs |journal=Science |volume=363 |issue= 6422|pages= 78–80|doi=10.1126/science.aal4853 |pmid=30467179 |bibcode=2019Sci...363...78S |doi-access=free |url=https://zenodo.org/record/2532919 }}{{cite news |last=St. Fleur |first=Nicholas |title=An Elephant-Size Relative of Mammals That Grazed Alongside Dinosaurs |url=https://www.nytimes.com/2019/01/04/science/dicynodonts-fossils-poland.html |date=4 January 2019 |work=[[The New York Times]] |access-date=6 January 2019 }}

Six fragments of fossil bone discovered in [[Queensland]], Australia, were interpreted as remains of a skull in 2003. This suggested by some author to indicate that dicynodonts survived into the [[Cretaceous]] in southern [[Gondwana]].{{cite journal |last1=Thulborn |first1=T. |last2=Turner |first2=S. |title=The last dicynodont: an Australian Cretaceous relict|journal=Proceedings of the Royal Society B: Biological Sciences|volume=270|issue=1518|year=2003|pages=985–993|doi=10.1098/rspb.2002.2296 |jstor=3558635 |pmid=12803915 |pmc=1691326 |bibcode=2003PBioS.270..985T }} The dicynodont affinity of these specimens was questioned (including a proposal that they belonged to a [[Baurusuchidae|baurusuchian]] crocodyliform by Agnolin et al. in 2010),{{cite journal |last=Agnolin |first=F. L. |author2=Ezcurra, M. D. |author3=Pais, D. F. |author4= Salisbury, S. W. |year=2010 |title=A reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: Evidence for their Gondwanan affinities |journal=Journal of Systematic Palaeontology |volume=8 |issue=2 |pages=257–300 |doi=10.1080/14772011003594870|bibcode=2010JSPal...8..257A |s2cid=130568551 |url=https://espace.library.uq.edu.au/view/UQ:206067/UQ206067.pdf }} and in 2019 Knutsen and Oerlemans considered this fossil to be of [[Pliocene|Plio]]-[[Pleistocene]] age, and reinterpreted it as a fossil of a large mammal, probably a [[Diprotodontidae|diprotodontid]] marsupial.{{cite journal |author1=Espen M. Knutsen |author2=Emma Oerlemans |year=2019 |title=The last dicynodont? Re-assessing the taxonomic and temporal relationships of a contentious Australian fossil |journal=Gondwana Research |volume=77 |pages= 184–203|doi=10.1016/j.gr.2019.07.011 |s2cid=202908716 |doi-access= }}

Six fragments of fossil bone discovered in [[Queensland]], Australia, were interpreted as remains of a skull in 2003. This suggested by some author to indicate that dicynodonts survived into the [[Cretaceous]] in southern [[Gondwana]].{{cite journal |last1=Thulborn |first1=T. |last2=Turner |first2=S. |title=The last dicynodont: an Australian Cretaceous relict|journal=Proceedings of the Royal Society B: Biological Sciences|volume=270|issue=1518|year=2003|pages=985–993|doi=10.1098/rspb.2002.2296 |jstor=3558635 |pmid=12803915 |pmc=1691326 |bibcode=2003PBioS.270..985T }} The dicynodont affinity of these specimens was questioned (including a proposal that they belonged to a [[Baurusuchidae|baurusuchian]] crocodyliform by Agnolin et al. in 2010),{{cite journal |last=Agnolin |first=F. L. |author2=Ezcurra, M. D. |author3=Pais, D. F. |author4= Salisbury, S. W. |year=2010 |title=A reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: Evidence for their Gondwanan affinities |journal=Journal of Systematic Palaeontology |volume=8 |issue=2 |pages=257–300 |doi=10.1080/14772011003594870|bibcode=2010JSPal...8..257A |s2cid=130568551 |url=https://espace.library.uq.edu.au/view/UQ:206067/UQ206067.pdf }} and in 2019 Knutsen and Oerlemans considered this fossil to be of [[Pliocene|Plio]]-[[Pleistocene]] age, and reinterpreted it as a fossil of a large mammal, probably a [[Diprotodontidae|diprotodontid]] marsupial.{{cite journal |author1=Espen M. Knutsen |author2=Emma Oerlemans |year=2019 |title=The last dicynodont? Re-assessing the taxonomic and temporal relationships of a contentious Australian fossil |journal=Gondwana Research |volume=77 |pages= 184–203|doi=10.1016/j.gr.2019.07.011 |s2cid=202908716 |doi-access= }}