Compositional changes during biomineralization of the radula of the chiton clavarizona hirtosa

For the radula of the chiton Clavarizona hirtosa, 14 segments consisting of five tooth rows each, and thus corresponding to teeth at different stages of mineralization, have been analyzed by PIXE for P, S, Cl, K, Ca, Fe, and Zn and by PIGME for F and Na. The composition of the radula changes appreciably during mineralization, with the concentration of the major element Fe increasing quite early. Subsequently, the concentrations of Zn and, even later, those of the three elements Ca, P, and F together increase appreciably. Little change was observed in the concentrations of Na, S, and Cl, while that of K increased slightly. These changes are related to the mineralization within the radula teeth of magnetite and a fluorine/carbonate-substituted apatite.