Landmark based thin plate spline relative warp analysis of gastropod shells

In the analysis of organismal form, landmark-based geometrical morphometrics now are preferred to traditional morphometrics by many systematists. However, certain forms have eluded geometrical morphometric analysis because landmarks on them are difficult to define; this situation is a problem of logistics rather than an inadequacy of the landmark-based approach. In this article, a landmark-based geometrical morphometric analysis is performed on one such form (the gastropod shell), and the results obtained are compared to those obtained using more traditional methods of morphometric analysis.