Odontode Explained

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.^[1] They generally do not have the same function as teeth, and are not replaced the same way teeth are in most fish.^[2] In some animals (notably catfish), the presence or size of odontodes can be used in determining the sex.^[3]

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.^[4]

Etymology

The name comes from the Greek "odous, gen. odontos" meaning tooth.

Images

Aquino et al. (2001) show scanning electron microscope images of odontodes on a catfish.^[5]

See also

• Dermal denticle

References

1. Web site: Paleos Vertebrates: Glossary . 2006-05-21 . https://web.archive.org/web/20060622200726/http://palaeos.com/Vertebrates/Lists/Glossary/GlossaryO.html . 2006-06-22 . dead .
2. News: Evolution of development of the vertebrate dermal and oral skeletons: Unraveling concepts, regulatory theories, and homologies . Paleobiology . 2002.
3. Web site: Sexual Dimorphism of the "Zebra Pleco" Hypancistrus zebra. 2006-05-22. https://web.archive.org/web/20060516193655/http://www.plecofanatics.com/forum/index.php?page=sexing_zebra_pleco. 2006-05-16. dead.
4. Dhouailly. Danielle. Godefroit. Pascal. Martin. Thomas. Nonchev. Stefan. Caraguel. Flavien. Oftedal. Olav. April 2019. Getting to the root of scales, feather and hair: As deep as odontodes?. Experimental Dermatology. en. 28. 4. 503–508. 10.1111/exd.13391. 28603898. 38481860. 0906-6705. free.
5. Aquino. Adriana E.. Schaefer. Scott A.. Miquelarena. Amalia M.. June 2001. A New Species of Hisonotus (Siluriformes, Loricariidae) of the Upper Río Uruguay Basin. American Museum Novitates. 3333. 1–12. 10.1206/0003-0082(2001)333<0001:ANSOHS>2.0.CO;2. 7469285 . 0003-0082.