A new paper by Marc Herbin and coleagues on coelacanth teeth was just published in the Journal of Structural Biology.

Read the abstract below:

The extant coelacanth Latimeria is a sarcopterygian predatory fish with caniniform teeth on its upper and
lower jaws. The teeth are constituted of a cone of dentine with an apical cap of enamel, and they are fixed
to the osseous component of the jaws by an attachment bone. Internal walls of the tooth base show folds
that have been firstly interpreted in the past as radial vascular canals. Three-dimensional visualisation of
these foldings using X-ray tomographic techniques and new histological interpretation lead to reconsider
these structures as true plicidentine. The folds of the dentine do not invade the whole pulp cavity of the
tooth contrary to the plicated condition of most fossil sarcopterygian fishes (e.g., Eusthenopteron,
Porolepis, Megalichthys) certain fossil marine reptiles (ichthyosaurs) and extant varanids; in Latimeria they
are limited to the lower third to the half of the pulp cavity. The presence of plicidentine in Latimeria’s
teeth is proposed to be a plesiomorphic character for sarcopterygians.