The teeth and dentition of the filefish (Stephanolepis cirrhifer) revisited tomographically

The upper and lower tooth-bearing jaws of the filefish (Stephanolepis cirrhifer) were scanned using a micro-CT system in order to address the existing gaps between the traditional pictures of the morphology and histology. 2D tomograms, reconstructed 3D models and virtual dissection were employed to examine and evaluate the in situ geometry of tooth implantation and the mode of tooth attachment both separately and collectively. No distinct sockets comparable to those in mammals were evident, but shallow depressions were observed in the premaxillary and the dentary. The opening of the tooth pulp cavity was not simply oriented towards the apparent tooth base in a direction opposite to the tooth apex. The opening was distorted basoposteriorly or basoanteriorly depending on the position of the tooth, and the edge of the pulp cavity opening was barely ankylosed; i.e. the sites of pleurodont ankylosis along the basoposterior or basoanterior edge of the opening appeared to closely match the contour of the shallow depression in the bone. These 3D findings appear to be very informative when considering the phylogeny of tooth attachment, suggesting that micro-CT would be a useful modality concurrent with or in advance of histological investigations.