Bichirs (f. Polypteridae) are the basal-most extant actinopterygians and studies of their feeding system may thus yield important insights into both the ancestral planform and the evolution of actinopterygian feeding mechanisms. In bichirs, as well as other gnathostomes, one of the functions of the sternohyoid muscle is to depress the hyoid and the mandible. The sternohyoid, along with the geniohyoid and hypaxials form a series of muscles that can either together or separately produce many kinematic outcomes, including hyoid depression. There is little literature examining how these muscles work together to produce vertical excursions of the hyoid in Actinopterygians, such as bichirs. We used biplanar x-ray videofluoroscopy to determine the relative contribution of the hypaxial and sternohyoid muscles to hyoid depression during chewing and food transport in bichirs. Our hypothesis was that the sternohyoid and hypaxial muscles contribute equally to hyoid depression. During phases of the intraoral feeding cycles where the hyoid was depressed 2.5 ± 1.4 mm (mean ± S.D.), the hypaxials lengthened by 0.2 ± 0.2 mm and the sternohyoid shortened by 0.2 ± 0.2 mm. When the hyoid was being elevated by 2.4 ± 1.13 mm, the hypaxials shortened by 0.2 ± 0.2 mm and the sternohyoid lengthened by 0.1 ± 0.2 mm. Our findings suggest that in bichirs, hyoid depression results from a combination of shortening of the sternohyoid and lengthening of the hypaxials, at odds with our hypothesis. It is possible that the sternohyoid acts as a connector for hypaxial and geniohyoid contractions; a hypothesis we are currently addressing. These data suggest that the ancestral condition for actinopterygians involves a complex interplay between hypaxial, suprahyoid and infrahyoid muscles in moving the hyoid during feeding.