Meeting Abstract
The family Soricidae is one of the most species-rich mammalian families and is present in all major temperate landmasses except Australasia. Although much attention has been given to studying taxonomic diversity, little work has been undertaken on the ecological disparity within the family. Here, we seek to determine if the disparity of cranial morphology among skulls of different shrew species reflects adaptations to their diverse diets. Indeed, although shrews are sometimes considered uniformly invertivorous, there are in fact variations in the size and hardness of the food consumed across species. As such, we expect variations in the biomechanical demands for different diets and consequently in skull morphology.
We used geometric morphometrics to capture variations in cranial morphology in a sample of 132 shrew specimens representing 41 species spanning all three sub-families of Soricidae. Each species was assigned to a diet category based on published literature. We placed landmarks and semi-landmarks on the lateral and ventral side of the skull and dentary to capture the size and shape of muscle attachments, teeth, and in-levers/out-levers. The results of our principal component analysis reveal that morphology is indeed linked to dietary ecology. Thus, for example, shorter snout width and dome-shaped skull are associated with processing larger and/or harder food. Our canonical variate analysis confirms that the diet of a shrew can be inferred from its morphology. An additional analysis including centroid size enables even better discrimination between diets and hints at the role of body size in determining the feeding range of shrews.
