Date of Award

12-2017

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Ecology and Evolutionary Biology

Major Professor

James A. Fordyce

Committee Members

Benjamin M. Fitzpatrick, Brian C. O'Meara, Elena D. Shpak

Abstract

Trophic divergence in cichlid fish is linked to morphological shifts in the pharyngeal jaw apparatus. For instance, in the Heroine cichlids of Central America, the ability to crush hard-shelled mollusks is a convergent phenotype with multiple evolutionary origins. These durophagous species often have very similar pharyngeal jaw morphologies associated with the pharyngeal jaw apparatus and some of these similarities could be due to phenotypically plastic responses to mechanical stress. I examined the durophagous cichlid Vieja maculicauda for differences in pharyngeal osteology, dentition, and soft tissues when exposed to different diet regimes. Here I discuss the effect on the morphology and gene expression of the pharyngeal jaw apparatus of varying mechanical stress without varying nutrient content, place this in a comparative framework, and discuss the effect of plasticity on morphological diversity.

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