Meeting Abstract

22.10  Wednesday, Jan. 4  Jaw Elongation and Piscivory in Fishes FERRY, LA*; GIBB, AC; Arizona State Univ; Northern Arizona Univ

Piscivory is a niche utilized by fishes due presumably to its obviously high energetic reward. However, eating other fish as food typically requires overcoming what has been termed 'gape-limitation'. Because fish tend to be among the largest prey organisms eaten by other fish, a large gape, as well as mechanisms for manipulating the large prey for transport are required. Many piscivorous lineages simply must grow into the piscivorous niche, waiting to attain a certain body size so that a minimum mouth size can also be achieved. Alternatively, several lineages independently have evolved jaw elongation associated with piscivory. Jaw elongation allows for a larger opening between the upper and lower jaw tips without concomitant changes to gape angle. Thus, the piscivorous niche is available to these species at a much smaller body size. Although the loss of features such as a lip ligament connecting the upper and lower jaws can assist with this, changes to the anatomy do not seem strictly necessary as the jaw opening mechanism (except for tip elongation) in largely conserved in several long-jawed species when comparing them with closely related short-jawed relatives from the same lineages. We illustrate this with kinematic data from prey-capture events from several independent lineages including the Esocidae, Cypriniformes, and Cyprinodontiformes.