Fish jaw
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Most bony fishes have two sets of jaws made mainly of bone. The primary oral jaws open and close the mouth, and a second set of pharyngeal jaws are positioned at the back of the throat. The oral jaws
Oral jaw from side and above of Piaractus brachypomus, a close relative of piranhas
Sailfish, like all billfish, have a rostrum (bill) which evolved from the upper jawbone
The paddlefish has a rostrum packed with electroreceptors
Sawfish have an electro-sensitive rostrum (saw) which is also used to slash at prey
Mandible
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In jawed vertebrates, the mandible, lower jaw, or jawbone is a bone that makes up the lower – and typically more mobile – component of the mouth.
Front view
Left side
Medial surface of the right body and ramus, the latter penetrated by the mandibular foramen (right)
German illustration with jawbones cut away to show the inferior alveolar nerve branching to the mandible's dental alveoli and passing through the mental foramen