CLARK, A. J.**; SUMMERS, A. P.; Univ. of California, Irvine; Univ. of California, Irvine: Functional morphology and kinematics of the hagfish feeding apparatus

Hagfish are basal craniates that lack jaws. Instead of jaws, hagfish possess a cartilaginous dental plate with two rows of cusps that resemble grasping dentition. A series of ventrally situated cartilaginous elements (the basal plate) support the dental plate and feeding muscles. During feeding, a network of protractor and retractor muscles pull on the dental plate resulting in a protraction-retraction movement. The protractor and retractor muscles behave in a manner analogous to gnathostome jaw abductor and jaw adductor muscles, respectively. Hagfish (Myxine glutinosa and Eptatretus stoutii) were housed in a glass aquarium with circulating ASW at 10�C. Feeding kinematics were recorded with a digital camera (30 fps) and analyzed with Adobe Premiere 6.0 and Image J. We measured bite cycle times and compared our results with those from several elasmobranch species. Hagfish bite cycle times were longer than previously recorded elasmobranch bite cycle times. Bite cycle times re-scaled to body length of the hagfish were longer than eight re-scaled elasmobranch bite cycle times. The longer bite cycle times of hagfish indicate a disadvantage of lacking jaws.