Meeting Abstract
Background: Flatfish (Pleuronectiformes) are characterized by asymmetry of the skull, with both eyes on one side of the head. Flatfish lay with their ‘blind’ side facing the sediment and ‘eyed’ side facing upward, using the pigmented, eyed side to blend into the sediment of the ocean floor beneath them. The urohyal is an ossified tendon of the sternohyoideus muscle, which attaches anteriorly to the hyoid. In ray-finned fish, this bone plays a large role in the mechanism responsible for the opening of the mouth. In flatfish, this bone also forms a channel between the left and right gill chambers, with branchiostegals on either side, allowing for water to pass between the chambers. Micro-CT scans of flatfish species were analyzed to collect data on the morphological variation of the urohyal, including whether or not it is attached to the hyoid, the number of branchiostegal rays surrounding the structure, size of the opercular bones, and the size and shape of the dorsal and ventral forks of the urohyal. We mapped these traits onto the Fish Tree of Life phylogeny to understand the evolution of traits and describe patterns based on burying behavior, habitat, and diet.
