Abstract
An eutactic star, in a n-dimensional space, is a set of N vectors which can be viewed as the projection of N orthogonal vectors in a N-dimensional space. By adequately associating a star of vectors to a particular sea urchin, we propose that a measure of the eutacticity of the star constitutes a measure of the regularity of the sea urchin. Then, we study changes of regularity (eutacticity) in a macroevolutive and taxonomic level of sea urchins belonging to the Echinoidea class. An analysis considering changes through geological time suggests a high degree of regularity in the shape of these organisms through their evolution. Rare deviations from regularity measured in Holasteroida order are discussed.
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López-Sauceda, J., Aragón, J.L. Eutacticity in Sea Urchin Evolution. Bull. Math. Biol. 70, 625–634 (2008). https://doi.org/10.1007/s11538-007-9273-2
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DOI: https://doi.org/10.1007/s11538-007-9273-2