Fig. 6. A in Size-shape relationships in the Mesozoic planispiral ammonites

Fig. 6. A. Plot of all individual measurements (n = 1222) of H2/D versus D showing relatively low variation in the Mesozoic Ammonoidea. The main trend H2/D = 0.3 is almost equal to the average <h2> = 0.303. B. Comparison of estimations of D versus actual measurements through the ontogeny of selected specimens (see Appendix 1 for details of material).</h2>