View source for Cynodontia

{{short description|Clade of therapsids}}
{{Distinguish|Conodont|Cynodon|Cynodontidae}}
{{Use dmy dates|date=October 2018}}
{{Automatic taxobox
| taxon = Cynodontia
| fossil_range = [[Late Permian]]-Recent, {{Fossil range|260|0|earliest=266}}
| image = Cynodontia2.png
| image_caption = 
Examples of cynodonts.<br />
1st row: ''[[Dvinia prima]]'', ''[[Trirachodon berryi]]'';<br />
2nd row: ''[[Brasilitherium riograndensis]]'', ''[[Megazostrodon rudnerae]]'';<br />
3rd row: ''[[Ornithorhynchus anatinus]]'' ([[platypus]]), ''[[Loxodonta africana]]'' ([[African bush elephant]]).
| authority = [[Richard Owen|Owen]], 1861
| subdivision_ranks = Clades
| subdivision = 
*†''[[Dvinia]]''
*†''[[Madysaurus]]''
*†[[Charassognathidae]]
*†[[Procynosuchidae]]
*[[Epicynodontia]]
}}

'''Cynodontia''' ({{ety|grc|''κύων'' (kúōn)|dog||''ὀδούς'' (odoús)|tooth}}) is a [[clade]] of [[eutheriodont]] [[therapsid]]s that first appeared in the [[Late Permian]] (approximately 260 [[Megaannum|mya]]), and extensively diversified after the [[Permian–Triassic extinction event]]. [[Mammal]]s are cynodonts, as are their extinct ancestors and close relatives ([[Mammaliaformes]]), having evolved from advanced [[probainognathia]]n cynodonts during the Late Triassic.

Non-mammalian cynodonts occupied a variety of [[ecological niches]], both as carnivores and as herbivores. Following the emergence of mammals, most other cynodont lines went extinct, with the last known non-mammaliaform cynodont group, the [[Tritylodontidae]], having its youngest records in the [[Early Cretaceous]].

== Etymology ==
The name cynodont ("dog tooth") comes from their cheek teeth, that can resemble a puppy's [[incisor]]s, which have [[Mamelon (dentistry)|mamelons]].<ref>{{cite web|author=Evolution Soup|title=When Mammals Were Reptiles - The Synapsid Story ~ with JULIEN BENOIT|url=https://www.youtube.com/watch?v=850Xd3mocio&t=892s|website=youtube.com |language=en |format=video |date=13 March 2022}}</ref>

== Description ==
[[File:140307-procynosuchus.JPG|left|thumb|270x270px|Skeleton of ''[[Procynosuchus]]'']]
Early cynodonts have many of the skeletal characteristics of [[mammal]]s. The teeth were fully differentiated and the braincase bulged at the back of the head. Outside of some [[Crown group|crown-group]] mammals (notably the [[theria]]ns), all cynodonts probably laid eggs. The [[temporal fenestrae#Fenestrae|temporal fenestrae]] were much larger than those of their ancestors, and the widening of the [[zygomatic arch]] in a more mammal-like skull would have allowed for more robust jaw musculature. They also have the [[secondary palate]] that other primitive [[therapsid]]s lacked, except the [[therocephalians]], who were the closest relatives of cynodonts. (However, the secondary palate of cynodonts primarily comprises the [[maxilla]]e and [[Palatine bone|palatines]] as in mammals, whereas the secondary palate of the therocephalians primarily comprises the maxillae and the [[vomer]].) The [[dentary]] was the largest bone in their lower jaw.
[[File:The American Museum journal (c1900-(1918)) (18161901551).jpg|left|thumb|Skull of ''[[Thrinaxodon]]'']]
The cynodonts probably had some form of [[warm-blooded]] metabolism. This has led to many reconstructions of cynodonts as having [[fur]]. Being endothermic they may have needed it for [[thermoregulation]], but fossil evidence of their fur (or lack thereof) has been elusive. Modern mammals have [[Harderian gland]]s secreting lipids to coat their fur, but the telltale imprint of this structure is only found from the [[mammaliformes|primitive mammal]] ''[[Morganucodon]]'' and onwards.<ref name=Fur>{{cite journal| last1=Ruben|first1= J.A. |last2= Jones| first2= T.D. |year=2000|title= Selective Factors Associated with the Origin of Fur and Feathers |journal=American Zoologist|volume= 40|pages= 585–596 | doi = 10.1093/icb/40.4.585 | issue=4|doi-access= free}}</ref> Nonetheless, recent studies on [[Permian]] synapsid [[coprolite]]s show that more basal therapsids may have had fur,<ref>{{cite journal | doi = 10.1111/let.12156 | title=Microbiota and food residues including possible evidence of pre-mammalian hair in Upper Permian coprolites from Russia | journal=Lethaia | year=2015 | last1 = Bajdek | first1 = Piotr| volume=49 | issue=4 | pages=455–477 }}</ref> and at any rate fur was already present in [[Mammaliaformes]] such as ''[[Castorocauda]]'' and ''[[Megaconus]]''.
[[File:Morganucodon skull.svg|left|thumb|Skull of ''[[Morganucodon]],'' a member of [[Mammaliaformes]]]]
Early cynodonts had numerous small [[Foramen|foramina]] on their snout bones, similar to reptiles. This suggests that they had immobile, non-muscular lips like those of lizards, and lacked muscular cheeks.<ref name=Estes1961/> As a muscular, mobile face is necessary to perform whisking movements and to avoid damage to [[whisker]]s, it is unlikely that early cynodonts had whiskers.<ref name=Benoit2016/><ref name=Benoit2020/> In [[prozostrodontian]] cynodonts, the group that includes mammals, the foramina are replaced by a single large infraorbital foramen, which indicates that the face had become muscular and that whiskers would have been present.<ref>{{Cite journal |last1=Benoit |first1=J. |last2=Manger |first2=P. R. |last3=Rubidge |first3=B. S. |date=2016-05-09 |title=Palaeoneurological clues to the evolution of defining mammalian soft tissue traits |journal=Scientific Reports |volume=6 |issue=1 |article-number=25604 |doi=10.1038/srep25604 |pmid=27157809 |pmc=4860582 |bibcode=2016NatSR...625604B |s2cid=4318400 |issn=2045-2322}}</ref>

Derived cynodonts developed [[epipubic]] bones. These served to strengthen the torso and support abdominal and hindlimb musculature, aiding them in the development of an erect gait, but at the expense of prolonged pregnancy, forcing these animals to give birth to highly [[altricial]] young as in modern [[marsupials]] and [[monotremes]]. Only [[placentals]], and perhaps ''[[Megazostrodon]]'' and ''[[Erythrotherium]]'', would lose these.<ref>Michael L. Power, Jay Schulkin. The Evolution of the Human Placenta. pp. 68–.</ref><ref>Jason A. Lillegraven, Zofia Kielan-Jaworowska, William A. Clemens, Mesozoic Mammals: The First Two-Thirds of Mammalian History, University of California Press, 17 December 1979 – 321</ref> A specimen of ''[[Kayentatherium]]'' does indeed demonstrate that at least tritylodontids already had a fundamentally marsupial-like reproductive style, but produced much higher litters at around 38 [[perinate]]s or possibly eggs.<ref>{{cite journal | last1 = Hoffman | first1 = Eva A. | last2 = Rowe | first2 = Timothy B. | year = 2018 | title = Jurassic stem-mammal perinates and the origin of mammalian reproduction and growth | journal = Nature | volume = 561 | issue = 7721| pages = 104–108 | doi = 10.1038/s41586-018-0441-3 | pmid = 30158701 | bibcode = 2018Natur.561..104H | s2cid = 205570021 }}</ref>

Cynodonts are the only known synapsid lineage to have produced aerial locomotors, with gliding being known in [[haramiyida]]ns<ref>{{cite journal | last1 = Meng | first1 = Qing-Jin | last2 = Grossnickle | first2 = David M. | last3 = Di | first3 = Liu | last4 = Zhang | first4 = Yu-Guang | last5 = Neander | first5 = April I. | last6 = Ji | first6 = Qiang | last7 = Luo | first7 = Zhe-Xi | year = 2017 | title = New gliding mammaliaforms from the Jurassic | journal = Nature | volume =  548| issue = 7667| pages =  291–296| doi = 10.1038/nature23476 | pmid = 28792929 | bibcode = 2017Natur.548..291M | s2cid = 205259206 }}</ref> and various mammal groups, and placental mammals having developed flight.<ref>{{Cite web | author= Basic Biology | date= 2015 | title= Bats | url= https://basicbiology.net/animal/mammals/bat}}</ref>

The largest known non-mammalian cynodont is ''[[Scalenodontoides]]'', a [[traversodontid]], which has been estimated to have a maximum skull length of approximately {{convert|617|mm|in}} based on a fragmentary specimen.<ref name="Tolchard2021"/>

==Evolutionary history==
{{See also|Evolution of mammals}}
[[Image:Thrinaxodon BW.jpg|thumb|right|200px| ''[[Thrinaxodon]]'' from the Early Triassic of South Africa]]
The closest relatives of cynodonts are [[therocephalia]]ns, with which they form the clade [[Eutheriodontia]].<ref name="AngielczykKammerer2018">{{Cite book|last1=Angielczyk|first1=Kenneth D.|url=https://www.degruyter.com/view/book/9783110341553/10.1515/9783110341553-005.xml|title=Mammalian Evolution, Diversity and Systematics|last2=Kammerer|first2=Christian F.|date=2018-10-22|publisher=De Gruyter|isbn=978-3-11-034155-3|editor-last1=Zachos|editor-first1=Frank|pages=117–198|chapter=Non-Mammalian synapsids: the deep roots of the mammalian family tree|doi=10.1515/9783110341553-005|editor-last2=Asher|editor-first2=Robert|s2cid=92370138}}</ref>

The earliest cynodonts are known early [[Lopingian]] (early [[Wuchiapingian]]) aged sediments of the [[Tropidostoma Assemblage Zone|''Tropidostoma'' Assemblage Zone]], in the [[Karoo Supergroup]] of South Africa, belonging to the basal family [[Charassognathidae]]. Fossils of Permian cynodonts are relatively rare outside of South Africa, with the most widely distributed genus being ''[[Procynosuchus]],'' which is known from South Africa, Germany, Tanzania, Zambia, and possibly Russia.<ref>{{Cite journal|last1=Huttenlocker|first1=Adam K.|last2=Sidor|first2=Christian A.|date=2020-12-01|title=A Basal Nonmammaliaform Cynodont from the Permian of Zambia and the Origins of Mammalian Endocranial and Postcranial Anatomy|url=https://www.tandfonline.com/doi/full/10.1080/02724634.2020.1827413|journal=Journal of Vertebrate Paleontology|language=en|volume=40|issue=5|article-number=e1827413|doi=10.1080/02724634.2020.1827413|bibcode=2020JVPal..40E7413H |s2cid=228883951 |issn=0272-4634|url-access=subscription}}</ref>

Cynodonts expanded rapidly in diversity after the [[Permian–Triassic extinction event]]. Peak disparity in cynodonts occurred from the Induan to the Carnian and in the middle Norian.<ref>{{Cite journal |last1=Ruta |first1=Marcello |last2=Botha-Brink |first2=Jennifer |last3=Mitchell |first3=Stephen A. |last4=Benton |first4=Michael James |date=22 October 2013 |title=The radiation of cynodonts and the ground plan of mammalian morphological diversity |journal=[[Proceedings of the Royal Society B: Biological Sciences]] |language=en |volume=280 |issue=1769 |article-number=20131865 |doi=10.1098/rspb.2013.1865 |issn=0962-8452 |pmc=3768321 |pmid=23986112 }}</ref> Post-Early Triassic cynodonts were dominated by members of the advanced clade [[Eucynodontia]], which has two main subdivisions, the predominantly herbivorous [[Cynognathia]] and the predominantly carnivorous [[Probainognathia]]. During the Early and Middle Triassic, cynodont diversity was dominated by members of Cynognathia, and members of Probainognathia would not become prominent until the Late Triassic (early [[Norian]]).<ref name="RBMB13" /> Almost all Middle Triassic cynodonts are known from Gondwana, with only one genus (''[[Nanogomphodon]]'') having been found in the Northern Hemisphere. Among the most dominant groups of Middle and Late Triassic cynodonts is the herbivorous [[Traversodontidae]], predominantly in Gondwana, which reached a peak diversity in the Late Triassic. [[Mammaliaformes]] originated from probainognathian cynodonts during the Late Triassic.<ref name=":0" /> Early Mammaliaformes were small bodied insectivores.<ref>{{Cite journal|last1=Grossnickle|first1=David M.|last2=Smith|first2=Stephanie M.|last3=Wilson|first3=Gregory P.|date=October 2019|title=Untangling the Multiple Ecological Radiations of Early Mammals|journal=Trends in Ecology & Evolution|language=en|volume=34|issue=10|pages=936–949|doi=10.1016/j.tree.2019.05.008|pmid=31229335 |s2cid=195327500 |doi-access=free}}</ref> Only two groups of non-mammaliaform cynodonts existed beyond the end of the Triassic, both belonging to Probainognathia. The first is the insectivorous [[Tritheledontidae]], which briefly lasted into the Early Jurassic. The second is the herbivorous [[Tritylodontidae]], which first appeared in the latest Triassic, which were abundant and diverse during the Jurassic, predominantly in the Northern Hemisphere, persisted into the Early Cretaceous ([[Barremian]]-[[Aptian]]) in Asia, at least until around 120 million years ago, as represented by ''[[Fossiomanus]]'' from China.<ref name=":0">{{Citation|last1=Abdala|first1=Fernando|title=The Late Triassic Record of Cynodonts: Time of Innovations in the Mammalian Lineage|date=2018|url=http://link.springer.com/10.1007/978-3-319-68009-5_11|work=The Late Triassic World|volume=46|pages=407–445|editor-last=Tanner|editor-first=Lawrence H.|place=Cham|publisher=Springer International Publishing|language=en|doi=10.1007/978-3-319-68009-5_11|isbn=978-3-319-68008-8|access-date=2021-05-24|last2=Gaetano|first2=Leandro C.|url-access=subscription}}</ref><ref name="Mao2021" />

During their [[evolution]], the number of cynodont [[jaw]] bones reduced. This move towards a single bone for the mandible paved the way for other bones in the jaw, the [[articular]] and [[Angular bone|angular]], to migrate to the cranium, where they function as parts of the mammalian hearing system.

Cynodonts also developed a [[secondary palate]] in the roof of the mouth. This caused air flow from the nostrils to travel to a position in the back of the mouth instead of directly through it, allowing cynodonts to chew and breathe at the same time. This characteristic is present in all mammals.

==Taxonomy==
[[Richard Owen]] named Cynodontia in 1861, which he assigned to [[Anomodontia]] as a family.<ref>[https://paleodb.org/cgi-bin/bridge.pl?action=startProcessPrintHierarchy&reference_no=16227&maximum_levels=100 Classification of R. Owen 1861].</ref> [[Robert Broom]] (1913) reranked Cynodontia as an infraorder, since retained by others, including Colbert and Kitching (1977), Carroll (1988), Gauthier ''et al.'' (1989), and Rubidge and [[Cristian Sidor]] (2001).<ref>[https://paleodb.org/cgi-bin/bridge.pl?action=startProcessPrintHierarchy&reference_no=14316&maximum_levels=100 Classification of B. S. Rubidge and C. A. Sidor 2001]</ref> Olson (1966) assigned Cynodontia to [[Theriodontia]], Colbert and Kitching (1977) to Theriodontia, and Rubridge and Sidor (2001) to [[Eutheriodontia]]. [[William King Gregory]] (1910), Broom (1913), Carroll (1988), Gauthier ''et al.'' (1989), Hopson and Kitching (2001) and Botha ''et al.'' (2007) all considered Cynodontia as belonging to Therapsida. Botha ''et al.'' (2007) seems to have followed Owen (1861), but without specifying taxonomic rank.<ref>R. Broom. 1913. A revision of the reptiles of the Karroo. Annals of the South African Museum 7(6):361–366</ref><ref>S. H. Haughton and A. S. Brink. 1954. A bibliographical list of Reptilia from the Karroo Beds of South Africa. Palaeontologia Africana 2:1–187</ref>

===Phylogeny===
[[Image:Procynosuchus NT.jpg|thumb|right|''[[Procynosuchus]]'']]
[[Image:Exaeretodon BW.jpg|thumb|right|''[[Exaeretodon]]'']]
[[Image:Diademodon.jpg|thumb|''[[Diademodon]]'']]
[[Image:Tritylodon BW.jpg|thumb|right|''[[Tritylodon]]'']]
[[Image:Oligokyphus BW.jpg|thumb|right|''[[Oligokyphus]]'']]

Below is a [[cladogram]] from Ruta, Botha-Brink, Mitchell and Benton (2013) showing one hypothesis of cynodont relationships:<ref name=RBMB13>{{Cite journal | last1 = Ruta | first1 = M. | last2 = Botha-Brink | first2 = J. | last3 = Mitchell | first3 = S. A. | last4 = Benton | first4 = M. J. | title = The radiation of cynodonts and the ground plan of mammalian morphological diversity | doi = 10.1098/rspb.2013.1865 | journal = Proceedings of the Royal Society B: Biological Sciences | volume = 280 | issue = 1769 | article-number = 20131865 | year = 2013 | pmid = 23986112| pmc = 3768321}}</ref>

{{clade| style=font-size:85%;line-height:85%
|label1=Cynodontia
|1={{clade
   |1=†''[[Charassognathus]]''
   |2={{clade
      |1={{clade
         |1=†''[[Dvinia]]''
         |2=†''[[Procynosuchus]]''}}
      |label2=[[Epicynodontia]]
      |2={{clade
         |1=†''[[Cynosaurus]]''
         |2={{clade
            |1={{clade
               |1=†''[[Galesaurus]]''
               |2=†''[[Progalesaurus]]''}}
            |2={{clade
               |1={{clade
                  |1=†''[[Nanictosaurus]]''
                  |2=†''[[Thrinaxodon]]''}}
               |2={{clade
                  |1=†''[[Platycraniellus]]''
                  |label2=[[Eucynodontia]]
                  |2={{clade
                     |label1=†[[Cynognathia]] 
                     |1={CYNOGNATHIA}
                     |label2=[[Probainognathia]]
                     |2={PROBAINOGNATHIA}
                     }} }} }} }} }} }} }}

|targetA ={CYNOGNATHIA}
|subcladeA={{Clade
   |1=''†[[Cynognathus]]''
   |label2=†[[Gomphodontia]]
   |2={{clade
      |1=''†[[Diademodon]]''
      |2={{clade
         |label1=†[[Trirachodontidae]]
         |1={{clade
            |1={{clade
               |1=''†[[Beishanodon]]''
               |2=''†[[Sinognathus]]''}}
            |2={{clade
               |1=''†[[Trirachodon]]''
               |2={{clade
                  |1=''†[[Cricodon]]''
                  |2=''†[[Langbergia]]''}} }} }}
         |label2=†[[Traversodontidae]]
         |2={{clade
            |1={{clade
               |1=''†[[Andescynodon]]''
               |2=''†[[Pascualgnathus]]''}}
            |2={{clade
               |1=''†[[Scalenodon]]''
               |2={{clade
                  |1=''†[[Luangwa (cynodont)|Luangwa]]''
                  |2={{clade
                     |1=''†[[Traversodon]]''
                     |2={{clade
                        |1={{clade
                           |1=''†[[Scalenodon attridgei|"Scalenodon" attridgei]]''
                           |2={{clade
                              |1=''†[[Mandagomphodon]]''
                              |2={{clade
                                 |1=''†[[Nanogomphodon]]''
                                 |2={{clade
                                    |1=''†[[Arctotraversodon]]''
                                    |2=''†[[Boreogomphodon]]''}} }} }} }}
                        |2={{clade
                           |label1=†[[Massetognathinae]]
                           |1={{clade
                              |1=''†[[Massetognathus]]''
                              |2={{clade
                                 |1=''†[[Dadadon]]''
                                 |2=''†[[Santacruzodon]]''}} }}
                           |label2=†[[Gomphodontosuchinae]]
                           |2={{clade
                              |1=''†[[Menadon]]''
                              |2={{clade
                                 |1=''†[[Gomphodontosuchus]]''
                                 |2={{clade
                                    |1=''†[[Protuberum]]''
                                    |2={{clade
                                       |1=''†[[Exaeretodon]]''
                                       |2=''†[[Scalenodontoides]]''}} }} }} }} }} }} }} }} }} }} }} }} }}

|targetB={PROBAINOGNATHIA}
|subcladeB={{Clade
   |1=†''[[Lumkuia]]''
   |2={{clade
      |1=†''[[Ecteninion]]''
      |2={{clade
         |1={{clade
            |1=†''[[Aleodon]]''
            |2=†''[[Chiniquodon]]''}}
         |2={{clade
            |1=†''[[Probainognathus]]''
            |2={{clade
               |1=†''[[Trucidocynodon]]''
               |2={{clade
                  |1=†''[[Therioherpeton]]''
                  |2={{clade
                     |label1=†[[Tritheledontidae]]
                     |1={{clade
                        |1=†''[[Riograndia]]''
                        |2={{clade
                           |1={{clade
                              |1=†''[[Chaliminia]]''
                              |2=†''[[Elliotherium]]''}}
                           |2={{clade
                              |1=†''[[Diarthrognathus]]''
                              |2=†''[[Pachygenelus]]''}} }} }}
                     |2={{clade
                        |label1=†[[Brasilodontidae]]
                        |1={{clade
                           |1=†''[[Brasilitherium]]''
                           |2=†''[[Brasilodon]]''}}
                        |2={{clade
                           |label1=†[[Tritylodontidae]]
                           |1={{clade
                              |1=†''[[Oligokyphus]]''
                              |2={{clade
                                 |1=†''[[Kayentatherium]]''
                                 |2={{clade
                                    |1=†''[[Tritylodon]]''
                                    |2=†''[[Beinotherium]]''}} }} }}
                           |label2='''[[Mammaliaformes]]'''
                           |2={{clade
                              |1=[[Mammalia]]
                              |2=†''[[Sinoconodon]]''
                              |3=†''[[Morganucodon]]''}} }} }} }} }} }} }} }} }} }} 
}}

==Distribution==
Non-mammalian cynodonts have been found in South America, India, Africa, Antarctica,<ref>{{cite journal|first1=Fernando|last1=Abdala|first2=Ana Maria|last2=Ribeiro|year=2010|title=Distribution and diversity patterns of Triassic cynodonts (Therapsida, Cynodontia) in Gondwana|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|volume=286|issue=3–4|pages=202–217|url=https://www.sciencedirect.com/science/article/abs/pii/S003101821000012X|doi=10.1016/j.palaeo.2010.01.011|bibcode=2010PPP...286..202A|url-access=subscription}}</ref> Asia,<ref name="Chinese Fossil Vertebrates">{{cite book|title=Chinese Fossil Vertebrates|last=Lucas|first=Spencer G.|year=2001|publisher=Columbia University Press|location=[[New York City]], [[Chichester]], [[West Sussex]]|isbn=0-231-08482-X|page=133|url=https://books.google.com/books?id=PSSRWCbm7gEC&q=Bienotherium&pg=PA133|access-date=November 30, 2019}}</ref> Europe<ref>{{cite book|title=In the Shadow of the Dinosaurs: Early Mesozoic Tetrapods|last1=Fraser|first1=Nicholas C.|last2=Sues|first2=Hans-Dieter|year=1997|publisher=Cambridge University Press}}</ref> and North America.<ref>{{cite journal|first1=Hans-Dieter|last1=Sues|first2=Paul E.|last2=Olsen|first3=Joseph G.|last3=Carter|year=1999|title=A Late Triassic Traversodont Cynodont From the Newark Supergroup of North Carolina|url=https://geodir.ldeo.columbia.edu/~polsen/nbcp/sues_et_al_99_sm.pdf|journal=Journal of Vertebrate Paleontology|volume=19|issue=2|pages=351–354|doi=10.1080/02724634.1999.10011146|bibcode=1999JVPal..19..351S }}{{Dead link|date=July 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

== See also ==
{{Portal|Paleontology}}
* [[Permian–Triassic extinction event]]
* [[Prehistoric mammal]]
* [[Tetrapod]]
* [[Triassic-Jurassic extinction event]]

== References ==
{{Reflist|refs=
<ref name=Estes1961>{{Cite journal| volume = 125| pages = 165–180| last = Estes| first = Richard| title = Cranial anatomy of the cynodont reptile Thrinaxodon liorhinus| journal = Bulletin of the Museum of Comparative Zoology| date = 1961}}</ref>
<ref name=Benoit2016>{{Cite journal| doi = 10.1038/srep25604| issn = 2045-2322| volume = 6| issue = 1| article-number = 25604| last1 = Benoit| first1 = J.| last2 = Manger| first2 = P. R.| last3 = Rubidge| first3 = B. S.| title = Palaeoneurological clues to the evolution of defining mammalian soft tissue traits| journal = Scientific Reports| date = 2016-05-09| pmid = 27157809| pmc = 4860582| bibcode = 2016NatSR...625604B}}</ref>
<ref name=Benoit2020>{{Cite journal| doi = 10.1007/s10914-019-09467-8| issn = 1064-7554 | eissn = 1573-7055| volume = 27| issue = 3| pages = 329–348| last1 = Benoit| first1 = Julien| last2 = Ruf| first2 = Irina| last3 = Miyamae| first3 = Juri A.| last4 = Fernandez| first4 = Vincent| last5 = Rodrigues| first5 = Pablo Gusmão| last6 = Rubidge| first6 = Bruce S.| title = The Evolution of the Maxillary Canal in Probainognathia (Cynodontia, Synapsida): Reassessment of the Homology of the Infraorbital Foramen in Mammalian Ancestors| journal = Journal of Mammalian Evolution| date = 2020| s2cid = 254702274 | url = http://link.springer.com/10.1007/s10914-019-09467-8| url-access = subscription}}</ref>
<ref name="Mao2021">{{Cite journal| doi = 10.1038/s41586-021-03433-2| issn = 0028-0836 | eissn = 1476-4687| last1 = Mao| first1 = Fangyuan| last2 = Zhang| first2 = Chi| last3 = Liu| first3 = Cunyu| last4 = Meng| first4 = Jin| title = Fossoriality and evolutionary development in two Cretaceous mammaliamorphs| journal = Nature| date = 2021-04-07| volume = 592 | issue = 7855 | pages = 577–582 | pmid = 33828300 | bibcode = 2021Natur.592..577M | s2cid = 233183060 | url = http://www.nature.com/articles/s41586-021-03433-2| url-access = subscription}}</ref>
<ref name="Tolchard2021">{{Cite journal| doi = 10.1080/02724634.2021.1929265| issn = 0272-4634| article-number = e1929265| last1 = Tolchard| first1 = Frederick| last2 = Kammerer| first2 = Christian F.| last3 = Butler| first3 = Richard J.| last4 = Hendrickx| first4 = Christophe| last5 = Benoit| first5 = Julien| last6 = Abdala| first6 = Fernando| last7 = Choiniere| first7 = Jonah N.| title = A new large gomphodont from the Triassic of South Africa and its implications for Gondwanan biostratigraphy| journal = Journal of Vertebrate Paleontology| date = 2021-07-26| volume = 41| issue = 2| bibcode = 2021JVPal..41E9265T| s2cid = 237517965}}</ref>
}}

==Further reading==
*{{cite journal | last1 = Hopson | first1 = J.A. | last2 = Kitching | first2 = J.W. | year = 2001 | title = A probainognathian cynodont from South Africa and the phylogeny of non-mammalian cynodonts | journal = Bull. Mus. Comp. Zool. | volume = 156 | pages = 5–35 }}
*Davis, Dwight (1961). "Origin of the Mammalian Feeding Mechanism". Am. Zoologist, 1:229–234.

==External links==
* [https://web.archive.org/web/20060313151442/http://www.palaeos.com/Vertebrates/Units/410Cynodontia/410.000.html Palaeos cynodonts]
* [http://www.helsinki.fi/~mhaaramo/metazoa/deuterostoma/chordata/synapsida/theriodontia/theriodontia_families.html#Mammaliaformes Phylogeny of Theriodonts and Cynodonts]
* [http://compphys.bio.uci.edu/bennett/pubs/74.pdf Bennett and Ruben 1986. The Metabolic and Thermoregulatory Status of Therapsids]
* [https://www.bbc.co.uk/nature/life/Cynodont BBC cynodonts]

{{Therapsida|N.|state=autocollapse}}
{{Cynodontia|E.|state=autocollapse}}
{{Taxonbar|from=Q131801}}

[[Category:Cynodontia| ]]
[[Category:Eutheriodontia]]
[[Category:Lopingian first appearances]]
[[Category:Extant Permian first appearances]]
[[Category:Taxa named by Richard Owen]]