Functional morphology of the Ocean Sunfish (Mola mola) Pharyngeal Jaw

Abstract

This study looked at the functional morphology of the ocean sunfish (Mola mola) pharyngeal jaw by looking at the general morphology, behavior under force, and the gelatinous prey retention of the pharyngeal jaws and teeth. This study demonstrates a novel use of pharyngeal teeth in fish, similar to structures found throughout the vertebrates that prevent the loss of ingested food and newly acquired prey items. We also discovered a functionally unique muscle to control the eversion of these teeth and other morphological characteristics (high safety factor, tooth replacement) that highlight the critical role of these teeth to the mola. Lastly, this study demonstrated that these teeth are likely only useful in adult fish, which follows the known ontogenetic diet shift.