In humans: Muscles arising in the zygomatic arch that close the jaw. Their nerve supply is masseteric from the mandibular division of the trigeminal nerve. (From Stedman, 25th ed).
Comment:
[development-note] "originate from the somitomeres. These muscles develop late and are not complete even at birth. Tongue muscles develop before masticatory muscles and complete by birth" xsd:string {source="http://php.med.unsw.edu.au/embryology"}