Why are there so many flatfishes? Jaw asymmetry, diet, and diversification in the Pleuronectiformes

Abstract

Flatfishes (Actinopterygii: Pleuronectiformes) are a diverse group of teleost fishes, with over 700 species in the order. Jaw asymmetry and diet have been thought to contribute to flatfish diversity but this has not yet been tested in a comparative framework. Here I use geometric morphometric and comparative methods to test whether ocular-blind side asymmetry in flatfish head morphology contributed to flatfish diversification. I find that the repeated convergent evolution of similar morphology, jaw function, and diet likely contribute to the high diversity of flatfishes.