Calcite orientations and composition ranges within teeth across Echinoidea

  • Stuart R Stock (Creator)
  • K. I. Ignatiev (Creator)
  • P. L. Lee (Creator)
  • J. D. Almer (Creator)



Sea urchin’s teeth from four families of order Echinoida and from orders Temnopleuroida, Arbacioida and Cidaroida were studied with synchrotron X-ray diffraction. The high and very high Mg calcite phases of the teeth, i.e. the first and second stage mineral constituents, respectively, have the same crystallographic orientations. The co-orientation of first and second stage mineral, which the authors attribute to epitaxy, extends across the phylogenic width of the extant regular sea urchins and demonstrates that this is a primitive character of this group. The range of compositions Δx for the two phases of Ca1- xMgxCO3 is about 0.20 or greater and is consistent with a common biomineralization process.
Date made available2020
PublisherTaylor & Francis

Cite this