Meeting Abstract
Historically, modes of teleost tooth replacement are classified as either intraosseus, wherein replacement teeth develop in sockets within the bone of attachment, or extraosseous, where replacement teeth develop within soft tissue outside the bone of attachment. However, recent work suggests that these modes of tooth replacement are extremes on a continuum and therefore understate the complexity of teleost tooth replacement. Salariin combtooth blennies (Blenniiformes: Blenniidae: Salariini) are a clade of teleost fishes that demonstrate an unusual mode of tooth attachment in which functional teeth are attached via loose connective tissue that may extend laterally beyond the jaw margins. Although tooth attachment has previously been described, these studies were limited by available technology. We use a range of methods including histology, SEM, microCT scanning and clearing and staining to ask two questions: 1) How are functional teeth replaced in the salariin blennies? 2) Do salariin blennies provide further evidence for a continuum of teleost tooth replacement modes? We find that replacement teeth develop and move labially through a matrix of highly vascularized epithelial and connective tissue, via a permanent, discontinuous dental lamina, to the functional tooth position. Most species exhibit teeth that at no point in development make contact with the oral jaw bones, and in some species, teeth are replaced within lip tissue lateral to the oral jaws. Salariin teeth are replaced extraosseously but their mode of attachment is unique, providing further evidence for a continuum tooth replacement classification model for teleost fishes.
