The morphology and evolution of tooth replacment in the combtooth blennies (Ovalentaria: Blenniidae)

Abstract

This research investigates the morphology and evolution of tooth replacement in the combtooth blennies. Blennies exhibit complex dentition that is not easily categorized by previously established metrics of teleost tooth replacement (extraosseous and intraosseous replacement). Most blennies are heterodont, possessing a single row of comb-shaped feeding teeth on the anterior portion of their jaws, and enlarged canines on the posterior portion of their lower jaws used for agonistic interactions. However, this bizarre dentition has been intentionally overlooked in classic surveys of teleost dentition due to its complexity. In Chapter 1, I investigate how feeding teeth are replaced in salariin blennies by establishing a descriptive model of tooth replacement for the Pacific Leaping Blenny, Alticus arnoldorum. This fish exhibits tooth replacement and tooth attachment that defy the discrete categorizations used for most other teleost dentitions. Using my descriptive model, I then propose hypotheses of how feeding teeth function in this fish. In chapter 2, I investigate how modes of tooth replacement have evolved in blennies. I find that canines in blennies are consistently replaced intraosseously, while feeding teeth across the family vary from intraosseous to a derived form of extraosseous replacement. These results further support the concept of teleost tooth replacement as a continuum rather than discretely classified modes. My results also suggest teleost tooth replacement needs to be carefully examined within a phylogenetic context to better understand how trophic morphological novelties evolve, as modes of tooth replacement likely play a key role in ecological and functional morphological shifts in teleosts.