Labridae Cuvier 1816

Labridae gen. et sp. indet. Fig. 25O–T Material examined UNITED STATES OF AMERICA – Mississippi • 12 isolated teeth; Catahoula Formation; SC 2013.28.603 (12 specimens) • 7 tooth masses; Catahoula Formation; SC 2013.28.596 (Fig. 25O–Q), SC 2013.28.597 (Fig. 25R–T), SC 2013.28.598 to 28.602. Description Our sample includes fragments of pharyngeal plates and isolated teeth. The pharyngeal plate fragments consist of tightly packed teeth of differing sizes that form a roughly contiguous surface. In cross section, up to four sets of replacement teeth are visible (Fig. 25Q, T). Teeth were apparently not replaced at a regular rate, as newer (replacement) teeth are intermingled with older functional teeth (Fig. 25O, R). In profile view, individual teeth can be low with a convex occlusal surface or high with a globular appearance. In occlusal/basal view, they have a circular to oval outline. Teeth essentially consist of a very thick enameloid cap with an open pulp cavity free of dentine (Fig. 25P, S). Remarks The unusual arrangement of the teeth within the jaw plates, as well as the composition of individual teeth, facilitates separating wrasse specimens from those of other, similar-looking taxa (see below). Fossil occurrences of Labridae are sparse, but Cicimurri et al. (2022) reported specimens from the Rupelian Ashley Formation of South Carolina, and Cicimurri & Knight (2009) mentioned their occurrence in the Chattian Chandler Bridge Formation. Labrid molecular divergence times were estimated by Cowman et al. (2009), who postulated that the extant lineages within this family largely diverged within the Miocene. This suggests that the labrid elements in our Catahoula Formation sample represent an unrecognized stem-member of the lineage.