Biology:Coronoid bone

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File:The Osteology of the Reptiles p30.png
Mandible of Dimetrodon (top) and Labidosaurus (bottom). The coronoid is labeled as cor.

The coronoid is a bone present in the mandible of many non-mammalian vertebrates. It typically lies on the medial wall of each hemimandible.[1] Among its functions, it provides a lever arm for the attachment of jaw muscles.

Evolution

In some actinoperygian fishes, the coronoid occurs near the anterior tip of the mandible and bears teeth.[2]

The coronoid is present in most sauropsids and amphibians.[3]

In early synapsids, the bone was present; it was progressively reduced during the evolution of mammals, and is absent in modern mammals. Its function has been taken over by the coronoid process of the dentary.[1]

In some animals, including some salamanders and parareptiles, the coronoid bears teeth.[4][5]

In some species, including the parareptile Delorhynchus and the fish Polypterus, multiple coronoid ossifications are present on each side.[5]

References

  1. ↑ 1.0 1.1 Kardong, Kenneth (2015) (in en). Vertebrates: Comparative Anatomy, Function, Evolution (7th ed.). New York: McGraw-Hill. ISBN 978-0-07-802302-6. 
  2. ↑ Jollie, M. (1984). "Development of the head and pectoral skeleton of Polypterus with a note on scales (Pisces: Actinopterygii)" (in en). Journal of Zoology 204 (4): 469–507. doi:10.1111/j.1469-7998.1984.tb02382.x. ISSN 1469-7998. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-7998.1984.tb02382.x. 
  3. ↑ Romer, A. S. (1956). Osteology of the Reptiles. Chicago: University of Chicago Press. 
  4. ↑ Vassilieva, Anna B.; Smirnov, Sergei V. (2001). "Development and Morphology of the Dentition in the Asian Salamander, Ranodon sibiricus (Urodela: Hynobiidae)" (in en). Russian Journal of Herpetology 8 (2): 105–116. doi:10.30906/1026-2296-2001-8-2-105-116. ISSN 1026-2296. http://rjh.folium.ru/index.php/rjh/article/view/574. 
  5. ↑ 5.0 5.1 Haridy, Yara; Macdougall, Mark J; Reisz, Robert R (2018-11-01). "The lower jaw of the Early Permian parareptile Delorhynchus, first evidence of multiple denticulate coronoids in a reptile". Zoological Journal of the Linnean Society 184 (3): 791–803. doi:10.1093/zoolinnean/zlx085. ISSN 0024-4082. https://doi.org/10.1093/zoolinnean/zlx085. 

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