Graduate Student University of Massachusetts Amherst Yarmouth Port, Massachusetts, United States
Abstract Body : The origin and evolution of the jaw is considered to be a highly consequential adaptive innovation in driving the diversification of vertebrates. Cichlid fishes provide a classic model to study the evolutionary trajectory of the vertebrate jaw as they demonstrate extensive adaptive radiation. East African cichlid fishes are characterized by widespread variation in jaw morphology between taxa in correspondence with foraging ecology. Here we use 3D morphometric analyses to examine patterns of variation in the cichlid gill arch, a critical component of the feeding apparatus. We find that several aspects of shape variation are predictive of foraging mode, including dorsal-ventral patterning. Additionally, we use QTL mapping in a hybrid cross between two ecologically distinct cichlids to characterize the genetic basis of gill arch variation. These results represent a first step toward understanding the specific genetic mechanisms regulating ecologically relevant differences in cichlid feeding anatomy. More broadly, the results contribute to our understanding of the developmental origins of variation in the vertebrate jaw.
