PREDATION INTENSITY AND MORPHOLOGICAL DISPARITY: DOES INCREASING PREDATION CONSTRAIN SHAPE IN MARINE GASTROPODS?

Predation is an important selective factor for many marine gastropods, and may drive the evolution of anti-predatory adaptations. Shell shape is controlled by developmental mechanisms, the cost of producing adaptations, fitness trade-offs, and abiotic factors. The complex suite of factors that lead to a specific morphology can be difficult to determine. This study examines multiple species and, within species, multiple populations of marine gastropods to assess whether particular aspects of shape correlate consistently with increasing predation pressure as indicated by repair scar frequency. Linear and geometric morphometric methods are used to compare morphological variations between populations and to look at shape disparity within populations.

The main questions asked are:

1. Does increasing predation constrain morphology along specific axes of shape space?

2. How does increasing predation affect overall morphological variability?

Using morphometric based techniques to look at covariation of shape and predation intensity may increase our understanding of what is driving the evolution of particular shapes in the fossil record: if aspects of shape vary consistently in their expression with increasing predation pressure, this may indicate an adaptive response. Conversely, a reduction in overall shape variation with increasing predation may indicate high selective pressures.