Calcite orientations and composition ranges within teeth across Echinoidea.
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.
['Stock|Stuart R|SR|', 'Ignatiev|Konstantin|K|', 'Lee|Peter L|PL|', 'Almer|Jonathan D|JD|']
D000818:Animals D002119:Calcium Carbonate D007091:Image Processing, Computer-Assisted D012617:Sea Urchins D014070:Tooth D014961:X-Ray Diffraction
calcite teeth sea urchin X-ray diffraction Biomineralization synchrotron radiation