{{short description|Teeth growing on the roof of the mouth}} [[File:Cotylorhynchus skull 2.jpg|thumb|Skull of the early synapsid ''[[Cotylorhynchus]]'', showing palatal dentition on the underside of the skull]] '''Palatal dentition''' refers to [[teeth]] that naturally grow on the bones of the roof of the mouth in some fish and [[tetrapod]]s (as opposed to the "marginal dentition" that grows at the edge of the mouth), either in rows or as a stippled covering referred to as a "shagreen". While ancestrally present in tetrapods, in many living tetrapod groups, including mammals, birds, turtles, and crocodilians, these teeth have been lost, though they are still retained in living [[Lepidosauria|lepidosaur]] reptiles and [[Lissamphibia|lissamphibians]].
== Description == [[File:Milleretta rubidgei (skull and reconstruction).png|thumb|Skull of the early reptile ''[[Milleretta rubidgei]]'' ([[Millerettidae]]), showing the development of palatal dentition on the [[vomer]] (labeled vo, tan), [[Palatine bone|palatine]] (pal, light red), [[Pterygoid bone|pterygoid]] (pt, green) and the parabasiphenoid (pbs, orange, formed from the fusion of the basisphenoid and [[parasphenoid]])]] In tetrapods, palatine teeth can occur on the [[vomer]], [[Palatine bone|palatine]], [[Pterygoid bone|pterygoid]] (including the pterygoid flange), [[ectopterygoid]], and [[parasphenoid]]. These teeth can either be placed in rows, similar to the marginal dentition on the edge of the mouth, or as a stippled covering referred to as a "shagreen". These teeth vary considerably in size and in some cases can exceed the size of the marginal teeth.<ref name=":0">{{Cite journal |last1=Matsumoto |first1=Ryoko |last2=Evans |first2=Susan E. |date=January 2017 |title=The palatal dentition of tetrapods and its functional significance |journal=Journal of Anatomy |language=en |volume=230 |issue=1 |pages=47–65 |doi=10.1111/joa.12534 |issn=0021-8782 |pmc=5192890 |pmid=27542892}}</ref>
== Occurrence == [[File:Muséum d'histoire naturelle de Bordeaux 104.jpg|thumb|Skull of a snake belonging to the genus ''[[Python (genus)|Python]]'', showing palatal tooth rows]] Palatal teeth are both present in [[Actinopterygii]] (ray-finned fish)<ref>{{Cite journal |last1=Huysseune |first1=A. |last2=Horackova |first2=A. |last3=Suchanek |first3=T. |last4=Larionova |first4=D. |last5=Cerny |first5=R. |date=2024-10-03 |title=Periderm fate and independence of tooth formation are conserved across osteichthyans |journal=EvoDevo |language=en |volume=15 |issue=1 |article-number=13 |doi=10.1186/s13227-024-00232-4 |doi-access=free |issn=2041-9139 |pmc=11451126 |pmid=39363199}}</ref> and [[Sarcopterygii]], and were inherited as an [[Plesiomorphy and symplesiomorphy|ancestral trait]] by the last common [[tetrapod]] ancestor. Palatal dentition is widespread amongst early tetrapods, though in many lineages of [[Amniote|Amniota]] the palatal dentition became reduced and in some cases entirely lost, the latter including [[Cynodontia|cynodonts]] (the ancestor of mammals), the ancestors of living turtles (though it is retained in very early stem turtles like ''[[Proganochelys]]''), as well as the vast majority of [[Archosaur|archosaurs]] (which includes [[Crocodilia|crocodilians]], [[Dinosaur|dinosaurs]] and their bird descendants), though a handful of archosaurs are known to retain a pterygoid tooth row, including the primitive dinosaurs ''[[Eodromaeus]]'' and ''[[Eoraptor]]'', and the primitive pterosaur ''[[Eudimorphodon]].'' Loss was not entirely uniform, and some lineages appear to have regained regions of palatal teeth that had been previously ancestrally lost. [[Lepidosaurian]] reptiles, including [[Squamata|squamates]] (lizards and snakes) and the [[tuatara]] as well as living [[Lissamphibia|lissamphibians]] retain palatal teeth. Some lizard groups have lost palatal teeth, including [[Gecko|geckoes]], [[Agamidae|agamids]] and [[Chameleon|chameleons]].<ref name=":0" /> Numerous lineages of [[Frog|frogs]] have also lost palatal teeth (often alongside the marginal teeth), while they are retained in all [[Salamander|salamanders]] and [[Caecilian|caecilians]].<ref>{{Cite journal |last1=Paluh |first1=Daniel J |last2=Riddell |first2=Karina |last3=Early |first3=Catherine M |last4=Hantak |first4=Maggie M |last5=Jongsma |first5=Gregory FM |last6=Keeffe |first6=Rachel M |last7=Magalhães Silva |first7=Fernanda |last8=Nielsen |first8=Stuart V |last9=Vallejo-Pareja |first9=María Camila |last10=Stanley |first10=Edward L |last11=Blackburn |first11=David C |date=2021-06-01 |title=Rampant tooth loss across 200 million years of frog evolution |url=https://elifesciences.org/articles/66926 |url-status=live |journal=eLife |language=en |volume=10 |article-number=e66926 |doi=10.7554/eLife.66926 |doi-access=free |issn=2050-084X |archive-url=http://web.archive.org/web/20250910232731/https://elifesciences.org/articles/66926 |archive-date=2025-09-10|pmc=8169120 }}</ref>
== Function == {{multiple image | align = center | total_width = | image1 = The Osteology of the Reptiles p50.png | alt1 = | image2 = Placodus gigas 3.jpg | alt2 = | footer = | caption1 = Skull and lower jaw of the [[edaphosaurid]] synapsid ''[[Edaphosaurus]]'', showing the development of a battery of palatal teeth on the pterygoid, ectopterygoid and palatine bones, along with a corresponding interlocking battery on the lower jaw, used to grind high fiber plant material | caption2 = Underside of the skull of the aquatic [[placodont]] reptile ''[[Placodus]]'', showing modification of palatal teeth into tooth plates used for crushing hard-shelled prey ([[durophagy]]) }}
Palatal dentition is widely thought to help manipulate food in the mouth in combination with the tongue, including by increasing grip, in some cases likely helping to restrain prey. In some lineages their function was modified. In [[Sphenodontidae]] (including the tuatara), the tooth row on the palatine bone is enlarged and orientated parallel to the upper marginal tooth row, with the lower marginal tooth row slotting between them, allowing for a shearing bite. In [[Placodontia]], they became plate-like and served to [[Durophagy|crush prey]].<ref name=":0" /> In advanced [[edaphosaurids]] like ''[[Edaphosaurus]]'', the teeth on the palatine, pterygoid and ectopterygoid were present on a raised battery, which interlocked with a similar battery on the lower jaw, which in ''Edaphosaurus'' served to grind high-fibre plant material.<ref>{{Cite journal |last=Mann |first=Arjan |last2=Henrici |first2=Amy C. |last3=Sues |first3=Hans-Dieter |last4=Pierce |first4=Stephanie E. |date=2023-04-05 |title=A new Carboniferous edaphosaurid and the origin of herbivory in mammal forerunners |url=https://www.nature.com/articles/s41598-023-30626-8 |journal=Scientific Reports |language=en |volume=13 |issue=1 |doi=10.1038/s41598-023-30626-8 |issn=2045-2322 |pmc=10076360 |pmid=37019927}}</ref><ref>Modesto SP (1995) [https://www.biodiversitylibrary.org/part/174219 The skull of the herbivorous synapsid ''Edaphosaurus boanerges'' from the Lower Permian of Texas]. Palaeontology 38, 213–239.</ref><ref name=":0" />
In living [[lungfish]], marginal teeth are entirely lost in adults, and the palatal teeth modified into crushing tooth plates.<ref>{{Cite journal |last1=Smith |first1=Moya Meredith |last2=Krupina |first2=Natasha I. |date=August 2001 |title=Conserved developmental processes constrain evolution of lungfish dentitions |url=http://www.journals.cambridge.org/abstract_S0021878201008172 |journal=Journal of Anatomy |volume=199 |issue=1 |pages=161–168 |doi=10.1017/S0021878201008172 |pmid=11523818 |url-access=subscription }}</ref> In many [[Snake|snakes]], the palatal tooth rows are used in combination with the marginal teeth (or alone in the case of [[elapids]] and [[viperids]]) to envelop the prey in the mouth and then moved via [[cranial kinesis]] to push prey further into the throat (the so-called "pterygoid walk").<ref>{{Cite journal |date=2006 |title=The Palatal Dentition in Squamate Reptiles: Morphology, Development, Attachment, and Replacement |url=http://www.bioone.org/doi/abs/10.3158%2F0015-0754%282006%29108%5B1%3ATPDISR%5D2.0.CO%3B2 |journal=Fieldiana Zoology |volume=108 |doi=10.3158/0015-0754(2006)108[1:TPDISR]2.0.CO;2|last1=Mahler|first1=D. Luke|last2=Kearney|first2=Maureen |page=1 |url-access=subscription }}</ref>
== References == {{Reflist}} [[Category:Teeth]]