Accepted abstract for ICVM 2010 meeting

Combining XROMM, electromyography and force measurements to investigate biomechanical and physiological aspects of durophagy in Cypriniform fishes

N.J. Gidmark and E.L. Brainerd; Brown University, Providence, RI, USA

Abstract accepted for the 9th International Congress of Vertebrate Morphology, July 26-31 2010, Punta Del Este, Uruguay.

Many vertebrates have evolved food processing (i.e. mastication) tools aside from the oral jaw apparatus. "Pharyngeal jaws" are derivations of gill arch structures co-opted for prey processing and are present in most fishes. Extreme modification in the pharyngeal jaw system is thought to have contributed to the proliferation of Perciform fishes — a clade of nearly 10,000 species. We currently have a good understanding of how biomechanical complexity in the oral and pharyngeal jaw systems power feeding ecology and evolution in that group. The second largest order of vertebrates — the Cypriniform fishes — demonstrates an entirely separate evolutionary shift to drastically derived pharyngeal jaws. The biomechanical consequences of pharyngeal jaw modification in cypriniform taxa have not been deeply investigated. I am combining classical muscle physiology studies with electromyography and XROMM to better understand pharyngeal jaw function. In-situ muscle preparations can generate tetanic length-tension curves for both of the jaw adductor muscles in the cypriniform pharyngeal jaw system, and I can relate those curves to length changes observed in-vivo, so long as both experiments are conducted in an XROMM setting. These data can help relate gape and force limitations observed in nature to physiological data measured in the laboratory. I can also investigate how a 2-adductor system can manage changes along either the force axis or the size axis of prey morphology, or concurrent changes along both axes.