On the Contribution of Allometry to Morphological Variation in a Freshwater Gastropod Elimia Livescens

Abstract

Morphological variation attributable to allometry in the freshwater gastropod Elimia livescens Menke, 1830 is described. Geometric morphometric analyses were used to examine shape variation and visual ontogenic deformation patterns for a population of E. livescens along the West Fork of the White River, Delaware County, Indiana. A strong allometric slope from more globose and robust shelled smaller individuals to increasingly fusiform shell shapes in larger individuals was identified. The relatively high allometric slope was interpreted as evidence of functional importance and maintenance through selection.