Comparative crystallography of vertebrate otoconia.

Otoconial material was obtained from a number of vertebrates to determine the CaCO3 polymorph present. Otoconia and otoliths from bony fish, amphibians, and reptiles are primarily aragonitic; those from birds and mammals are calcitic. This paper summarizes data from all other investigators as well as presenting new data, particularly pertaining to reptiles. The significance, if any, of the relationship between taxonomic group and carbonate polymorph remains an intriguing question.