Meeting Abstract
Prey capture is a functionally integrated endeavor: the body moves to the food, the capturing tools (e.g. teeth, jaws, and appendages) interact with the food, and the muscular system is moves the body and jaws. Centrarchid fishes (37 species) are a fantastic model system for studying the integrated evolution of these systems, because they show variation in body shape and mouth shape, and because jaw-closing mechanics are governed largely by a single adductor muscle complex. We examined anatomy in this group in terms of three attributes: body shape, jaw musculoskeletal structure, and jaw-closing (adductor) muscle physiology. We used CT scans, digital photography, physical dissection, and in situ muscle preparations in our exploration. Our results show that diversity in this group is rich in each of those three attributes. For example, the body shape of green sunfish and largemouth bass is torpedo-like, whereas bluegull sunfish, crappie, and redear sunfish show plate-like body shapes. Interestingly, variation in body shape is not correlated directly with variation in jaw shape; crappie and largemouth bass share similar jaw shapes, despite widely different body forms. Physiological in situ muscle preparations (force-velocity and force-length) show high diversity in muscle performance, even with skeletal (jaw) anatomy taken into account. Preliminary analyses indicate a tighter correlation of jaw muscle physiology with jaw shape than with body form. Continuing work aims to increase the species-level sample size for muscle preparations (currently N = 4 individuals each for 5 species for force-length and N = 4 individuals each for 5 species for force-velocity experiments) to better match that of our CT scan dataset (N = 1 individual each of 37 species) and to rigorously test phylogenetic integration of these traits.
