Meeting Abstract

1.1  Wednesday, Jan. 4  Ontogenetic scaling of the morphology and biomechanics of the feeding apparatus in the Pacific hagfish Eptatretus stoutii CLARK, A/J*; SUMMERS, A/P; College of Charleston; Friday Harbor Laboratories, Univ. of Washington clarkaj@cofc.edu

The scaling patterns of feeding systems can indicate feeding habits and ontogenetic dietary changes. The form and function of the support skeleton, musculature and teeth were examined in an ontogenetic series of Pacific hagfish Eptatretus stoutii spanning about a six-fold range in total length. Tooth area, feeding apparatus length, basal plate size, theoretical dental plate retractile force, penetration force, and applied tooth stress were measured relative to body size. Morphological variables (e.g. tooth area and basal plate size) scaled with positive allometry and functional variables (e.g. retractile force and applied tooth stress) scaled isometrically with total length. These results suggest that juveniles do not undergo ontogenetic dietary changes and consume functionally equivalent prey to adults, though adults can grasp proportionally larger portions of food. Low tooth stress in juveniles and adults imposes mechanical constraints to puncturing and tearing, which are circumvented by a preference for softer prey tissue or the inclusion of knotting behaviors for reducing tougher prey.