Figure 2From: Evolutionary tradeoffs, Pareto optimality and the morphology of ammonite shells Raup morphospace coordinates. Ammonoid shell morphology can be described by three dimensionless geometrical parameters: W, the whorl expansion rate, is defined by a/b in the figure. D, the internal to external shell ratio, is x/a. S, the opening shape parameter, is y/z. The shell diameter can also be related to the parameters in this figure as shown.Back to article page