Meeting Abstract
The taxonomic, functional, and morphological richness of life on Earth is distributed unevenly across the globe, following gradients dictated by both biotic and abiotic factors. The marine Bivalvia, a diverse, widespread clade that in many ways mirrors global shallow-marine diversity patterns, provides a model system for asking questions about spatial patterns in different aspects of richness. Here we analyze morphological patterns and their correlates along a latitudinal gradient. Bivalve shell morphology is a compromise among anatomical constraints, resource allocation strategies, and functional requirements dictated by the environmental conditions the animal lives in. We use 3D micro-CT scans of the rich Florida Keys bivalve fauna (c. 360 species) to quantify internal biovolume, shell-material volume, and internal and external surface areas (including ornamentation), enabling us to evaluate the controls of shell construction, comparing tropical specialists to wider-ranging generalist taxa in a phylogenetic context. Early analyses suggest that Keys-resident taxa that range further north have shells that are thinner relative to their biovolume, less complex external surface areas, and potentially are allocating fewer resources to shell building, than those co-occurring taxa that are restricted to the tropical latitudes. There is also a narrowing of variance of interspecific shell form with increasing northern latitudinal extent – indicating convergence in aspects of morphology regardless of taxonomic affinity, and potentially, trade-offs in morphology for greater environmental range.
