CONCLUSIONS

The results presented in this paper underscore our fundamental lack of understanding of septal formation in ammonoids. Why is it important to develop a sound model for the formation of septal folding in ammonoids? First, such a model may help us better understand the biological function of these folds, which has been the subject of heated debate for decades (see references in Introduction). Second, the recurrent formation of septa through ontogeny provides an especially detailed window into the growth processes of these cephalopods. The tension between developmental constraints and developmental plasticity has been suggested as a key factor in ammonoids' remarkably rapid evolutionary rates (Yacobucci 1999, 2004). Hence, by providing a way to measure and study developmental plasticity, the investigation of sutural variations may shed light on the evolutionary processes that produced such an extraordinary array of molluscan forms.

The study presented here only scratches the surface of GIS' potential as a powerful analytical tool in paleontology. GIS approaches hold great promise for addressing a wide range of questions in ammonoid paleobiology, and are also amenable to investigating the many other complex morphologies found among ancient organisms (e.g., conodonts, see Manship et al. 2006). Most earth science departments and many biology departments already hold licenses for GIS software, providing widespread access to state-of-the-art spatial analysis tools that paleontologists have only begun to exploit.