hyomandibula
thumb|Skeletal head of an Bowfin|Amia calva. Hyamandibular marked h, top image, upper right corner The hyomandibula, commonly referred to as hyomandibular [bone] (, from , "upsilon-shaped" (υ), and Latin: mandibula, "jawbone"), is a set of bones that is found in the hyoid region in most fishes. It usually plays a role in suspending the jaws and/or operculum (teleostomi only). It is commonly suggested that in tetrapods (land animals), the hyomandibula evolved into the columella (stapes).
Article
4 sectionsContents
- Evolutionary context
- See also
- Notes
- References
thumb|Skeletal head of an Bowfin|Amia calva. Hyamandibular marked h, top image, upper right corner The hyomandibula, commonly referred to as hyomandibular [bone] (, from , "upsilon-shaped" (υ), and Latin: mandibula, "jawbone"), is a set of bones that is found in the hyoid region in most fishes. It usually plays a role in suspending the jaws and/or operculum (teleostomi only). It is commonly suggested that in tetrapods (land animals), the hyomandibula evolved into the columella (stapes).
== Evolutionary context == In jawless fishes, a series of gills opened behind the mouth, and these gills became supported by cartilaginous elements. The first set of these elements surrounded the mouth to form the jaw. There is ample evidence that vertebrate jaws are homologous to the gill arches of jawless fishes. The upper portion of the second embryonic arch supporting the gill became the hyomandibular bone of jawed fishes, which supports the skull and therefore links the jaw to the cranium.