Fig. 4. Statistical test of potential dimorphism in Lewesiceras peramplum (Mantell, 1822) based on 63 specimens. The repository number of each specimen is given on top of the diagram. A. Classical clustering; the red color characterises particularly small individuals with D <77 mm in between the group of potential microconchs. B. Linear discriminant analysis (LDA); the color code follows the assignment of the classical clustering above. The dark blue lines are biplots of all variables, an overlaying of a score plot and a loadings plot in a single graph, which enables to visualise high-dimensional data by using a two-dimensional graph.