A CRYSTALLOGRAPHIC STUDY OF VERTEBRATE OTOLITHS

Abstract

Otoliths from 58 species were studied by polarization microscopy and X-ray diffraction. Otoliths occur as statoconia (single crystals or polycrystalline), microstatoliths and stato-liths (polycrystalline). Endogenous otoliths are composed of apatite, calcite, aragonite, vaterite or CaCO3[center dot]H2O. The distributions of otolith types, textures and minerals in the Vertebrate show consistencies within higher taxa and potentially interesting discrepancies. That this type of study yields information on the functions of otoliths and on vertebrate phylogeny is discussed.