BEMIS, W.E.; GIULIANO, A.; Univ. of Massachusetts, Amherst; Univ. of Massachusett, Amherst: Structure, Attachment, Replacement and Growth of Teeth in Bluefish (Pomatomus saltatrix), a Teleost with Deeply Socketed Teeth

Tooth replacement poses many questions about development, pattern formation, tooth attachment mechanisms, functional morphology and the evolution of vertebrate dentitions. Although most vertebrate species have polyphyodont dentitions, detailed knowledge of tooth structure and replacement is poor for most groups, particularly actinopterygians. We report on the dentition of the bluefish, Pomatomus saltatrix, a pelagic marine teleost known for its predatory habits. The teeth of Pomatomus are sharp, deeply socketed and firmly ankylosed to the bone of attachment. Replacement occurs in approximately alternate series, with long waves of replacement passing from rear to front; no evidence of reversing waves of replacement was found. The number of teeth increases ontogenetically, ranging from 15 to 31 dentary teeth and 15 to 39 premaxillary teeth in the sample studied. The teeth also increase in size with every replacement cycle, but the effects of crowding caused by these larger replacement teeth are difficult to measure. Remodeling of the attachment bone and adjacent teeth occurs continuously to accommodate growth, but the overall result of that growth is isometric. New tooth germs originate from a discontinuous dental lamina and migrate from the lingual (dentary) or labial (premaxillary) epithelium through pores in the bone of attachment into the resorption spaces beneath the existing teeth. As noted long ago by Richard Owen, patterns of tooth replacement in fishes can be compared instructively to those of crocodilians. This paper is a contribution to the symposium honoring Marvalee Wake, and recognizes in particular her contributions to the study of teeth. Supported by NSF DEB 0075460 and the Jane H. Bemis Fund for Research in Natural History.