Constructional morphology of strombid gastropods

Abstract

The extreme diversity in shell shape of strombid gastropods is interpreted as the result of three independent factors: (1) The terminal growth pattern of the Strombidae allows the circumvention of geometric constraints on shell morphology found in gastropods with continuous or periodic growth patterns. (2) Shell morphology in the Strombidac is adaptive in epifaunal locomotion, burrowing. infaunal or semi‐infaunal habits, and passive protection from predators. Specialization for one of these functions often conflicted with the others. thus bringing about a forced ‘choice’ among mutually exclusive morphological characters. (3) Conservatism in life habits and anatomy of the soft parts has allowed the multiple evolution of extreme shell morphologies, as well as the secondary return to relativcly unspecialized morphologies.