Elliptical Fourier Functions as a Morphological Descriptor of the Genus Stenosarina (Brachiopoda, Terebratulida, New Caledonia)
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- Tort, A. Mathematical Geology (2003) 35: 873. doi:10.1023/B:MATG.0000007784.18452.73
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The present-day brachiopod genus Stenosarina from New Caledonia, which comprises two species—S. globosa and S. crosnieri—and a third indented form known as lobate Stenosarina, has not been described in the literature. To investigate the morphological variability of the genus Stenosarina and to determine how the lobate form is related to the first two species, 57 specimens were studied by means of elliptical Fourier functions. Harmonics 2–11 were used as outline descriptors. The harmonics describing each outline and then their Fourier coefficients were compared using factor analysis. The study showed that Fourier functions provide accurate descriptors and allow for precise comparisons of brachiopod outlines. Moreover, harmonic coefficients were found to be more informative than harmonic amplitudes. The results revealed a marked morphological disparity within the genus Stenosarina. The lobate Stenosarina appeared to be morphologically closer to S. crosnieri than to S. globosaand may therefore be considered as an endemic variant of S. crosnieri.