Exploring Cichlid fish tooth regeneration turnover rates

Abstract

Polyphyodonts are organisms who can continuously replace their teeth throughout their lives, yet this mechanism is extremely complex. There are many factors that can affect tooth density and turnover rate, including genetic predisposition and environmental stimuli. In this study, we use pulse chase experiments to investigate the tooth turnover rates of polyphyodont cichlid fish species with differing tooth densities and morphologies. The experiments were carried out with 15-20 day old cichlids from the species Cynotilapia afra and Metriaclima zebra, which are unicuspid and bicuspid respectively. Alizarin-red and Calcein green fluorescent dye were applied in succession with varied timing, and dye incorporation patterns were then analyzed to distinguish recently replaced teeth from older teeth. C. afra have a lower density unicuspid teeth and M. zebra have a higher density of bicuspid teeth. Preliminary results suggest that the C. afra had slower tooth regeneration when compared to the M. zebra jaws, as Alizarin dye incorporation was much more prevalent in the unicuspid jaws; however, the M. zebra jaws featured many more half red/half green teeth and a larger number of Calcein-only replacement teeth that began to form a distinct, second row. Thus, after compiling the preliminary results, the data suggests that the unicuspid species C. afra has a slower tooth turnover rate than the bicuspid species M. zebra, but a larger sample size is needed to confirm these assertions.