odontode

{{Redirect|Odontodes|the genus of moth|Odontodes (moth)}}

Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings. They consist of a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to that of teeth.{{cite web | url = http://www.palaeos.com/Vertebrates/Lists/Glossary/GlossaryO.html | title = Paleos Vertebrates: Glossary | access-date = 2006-05-21 | archive-url = https://web.archive.org/web/20060622200726/http://palaeos.com/Vertebrates/Lists/Glossary/GlossaryO.html | archive-date = 2006-06-22 | url-status = dead }} They generally do not have the same function as teeth, and are not replaced the same way teeth are in most fish.{{cite news | url = http://www.findarticles.com/p/articles/mi_qa4067/is_200210/ai_n9111235/pg_10 | title = Evolution of development of the vertebrate dermal and oral skeletons: Unraveling concepts, regulatory theories, and homologies | work=Paleobiology | year=2002}} In some animals (notably catfish), the presence or size of odontodes can be used in determining the sex.{{cite web| url = http://www.plecofanatics.com/forum/index.php?page=sexing_zebra_pleco| title = Sexual Dimorphism of the "Zebra Pleco" Hypancistrus zebra| access-date = 2006-05-22| archive-url = https://web.archive.org/web/20060516193655/http://www.plecofanatics.com/forum/index.php?page=sexing_zebra_pleco| archive-date = 2006-05-16| url-status = dead}}

Odontodes typically cover the body of chondrichthyans (cartilaginous fishes), while mineralized dermal scales are characteristic of bony fishes. During the evolution to bony fishes, ancestral odontodes have been modified to become dermal scales, including elasmoid scales in teleosteans.{{Cite journal|last1=Dhouailly|first1=Danielle|last2=Godefroit|first2=Pascal|last3=Martin|first3=Thomas|last4=Nonchev|first4=Stefan|last5=Caraguel|first5=Flavien|last6=Oftedal|first6=Olav|date=April 2019|title=Getting to the root of scales, feather and hair: As deep as odontodes?|journal=Experimental Dermatology|language=en|volume=28|issue=4|pages=503–508|doi=10.1111/exd.13391|pmid=28603898|s2cid=38481860|issn=0906-6705|doi-access=free}}