Ecophenotypy, temporal and spatial fidelity, functional morphology, and physiological trade-offs among intertidal bivalves

Ecophenotypic variation in populations is driven by differences in environmental variables. In marine environments, ecophenotypic variation may be caused by differences in hydrodynamic conditions, substrate type, water depth, temperature, salinity, oxygen concentration, and habitat heterogeneity, among others. Instances of ecophenotypic variation in modern and fossil settings are common, but little is known about the influences of time-averaging and spatial-averaging on their preservation. Here we examine the shell morphology of two adjacent populations, both live-collected and death assemblages, of the infaunal, suspension-feeding, intertidal bivalve Leukoma staminea from the well-studied Argyle Creek and Argyle Lagoon locations on San Juan Island, Washington, USA. Individuals in the low energy lagoon are free to burrow in the fine-grained substrate while clams in the high energy creek are precluded from burrowing in the rocky channel. Our results demonstrate variation in size and shap...