Meeting Abstract

76.1  Sunday, Jan. 6  Hyoid system in specialized and generalized gasterosteiforms LEYSEN, H.*; ADRIAENS, D.; Ghent University, Belgium; Ghent University, Belgium

The family of Syngnathidae (Gasterosteiformes) encompasses the pipefishes and seahorses. Apart from the prehensile seahorse tail and the elongated pipefish body, syngnathids are characterized by a remarkable cranial morphology with an elongated snout. This snout enables them to perform very fast and powerful suction feeding. In fact, pipefishes and seahorses achieve prey capture times of even less than 6 ms, being among the fastest teleost feeding intake ever recorded. As in most suction feeders, these extremely fast feeding strikes are accomplished through an increase in buccal cavity volume as a consequence of rapid expansion of the head. This expansion is a result of an explosive retraction of the hyoid in combination with very rapid neurocranial elevation. Although the hyoid arch plays a crucial role in the whole feeding mechanism, very little is known about its detailed morphology and its linkages with other elements involved in feeding. In this presentation a thorough osteological and myological description of the hyoid arch of a pipefish (Dunckerocampus dactyliophorus) as well as a seahorse representative (Hippocampus reidi) will be given based on in toto cleared and stained specimens, dissections, serial histological sectioning, graphical 3D-reconstruction and CT-scans. Furthermore, a comparison with a more basal and generalized gasterosteiform (Gasterosteus aculeatus) will make it possible to place the observed features in an evolutionary context.