Hydrodynamic sorting in a coastal marine skeletal assemblage

In this paper I evaluate the effects of wave and tidal erosion on element-specific measures of phenotypic variability. Previous research has found a high correlation between skeletal weight, shape, and density and the transport potential of an element exposed to hydrodynamic forces. However, no previous studies have attempted to address the issue of within-element sorting based on selective removal of only the smallest members of a given element class. I evaluate this hypothesis using a human skeletal sample from Bird Island (8DI52) located in Dixie County, Florida. This sample comprises two components, an eroded sample that was exposed during severe storm and tidal activity, and an uneroded sample excavated from primary context. The measurement-specific means for the subcomponents were compared using Student's t and Wilcoxon tests and variability differences were evaluated based on standard deviations, coefficients of variation, and maximum/minimum indices. The data included maxillary and mandibular tooth dimensions and postcranial metrics. No evidence for selective winnowing based on within-element size was found in this data set.