branchial arch

branchial arch (plural branchial arches)

1. (zoology, fish anatomy) Any of a series of bony looped structures which support the gills of fish; any of the pharyngeal arches in a fish embryo.

   Synonym: gill arch

• The branchial arches proper (i.e., those arches that support the gills) of a fish arise from certain of the pharyngeal arches that form in embryo.
• Pharyngeal arches form in the embryo of all vertebrates, although their number varies.
  • The first, called the mandibular arch, develops into the jaws.
  • The second, the hyoidal arch, becomes the hyomandibular complex, which supports the back of the jaw and (when gills are present) the front of the gill series.
  • In gilled vertebrates (chiefly fish), the remaining arches become the branchial arches, which support the gills. In amphibians and reptiles, they give rise to other structures. In birds and mammals, the hyoidal arch, too, has significantly evolved.
• Each branchial arch consists of the same series of paired (left and right) elements. From dorsal-most (highest) to ventral-most (lowest), these are: pharyngobranchial, epibranchial, ceratobranchial, hypobranchial, basibranchial.
• The hyoidal arch follows a similar pattern: pharyngohyal (present in only one taxonomic order), epihyal, ceratohyal, hypohyal, basihyal.

• pharyngeal arch

• Pharyngeal arch on Wikipedia.Wikipedia