Meeting Abstract
P2.70 Jan. 5 Mechanics of suction generation during feeding in Little skates DUQUETTE, D.C.*; WILGA, C.D.; Univ. of Rhode Island; Univ. of Rhode Island dduquette@mail.uri.edu
Feeding mechanisms of aquatic vertebrates has been extensively studied in the past, while that of elasmobranchs remains limited. Comparing feeding mechanisms in skates and sharks may shed light on morphological transformations that have arisen after the evolutionary split of these two groups. In this study prey capture and manipulation behaviors are compared in two benthic feeding elasmobranchs, Little skates and white-spotted bamboo sharks. Jaw kinematics and buccal pressure during feeding events are investigated using sonomicrometry simultaneously with pressure transducers. Little skates capture prey primarily using biting but sometimes utilize weak suction as well. Pressure in the buccal cavity during prey capture varies around ambient ranging from slightly positive to slightly negative. In contrast bamboo sharks always use strong suction to capture prey with greater subambient buccal pressures. However, both species extensively process prey using strong suction alternately with compression. Such cycles can last several seconds, eventually ending in transport of the prey item. Greater subambient pressure develops in the buccal cavity during manipulation, indicating that skates are capable of generating stronger suction than that used to capture prey. Gape expansion during capture events is greater than during manipulation. Hyoid expansion attains similar magnitudes in both capture and manipulation events. Time of mean onset, peak gape and hyoid expansion occurs prior to peak buccal pressure in captures and manipulations. Although both occupy benthic regions of the ocean, prey capture in the two species appears to be quite different while manipulations are similar. Morphological differences in the jaw and hyoid apparatus of sharks and skates may be partly responsible for the functional differences in the generation of suction.
