REASSESSING BURGESS SHALE TROPHIC STRUCTURE

Cambrian and modern oceans appear ecologically distinct. Whereas the Cambrian was dominated by generalized deposit feeders, modern communities display a wide range of functional diversity as well as an established plankton ecosystem. Despite these large differences in community composition, previous work identified structural similarities between Cambrian and modern food webs. Here, we reassess the trophic structure of Cambrian marine communities in two ways: i) by combining established approaches to ancient food-web creation with updated assessments of species interactions, and ii) by applying a functional diversity-based model of food web connections to data from numerous Burgess Shale assemblages. We identified differences in community structure between Burgess Shale assemblages, including differences in degree of generalization among predators and complexity. Furthermore, in contrast to previous results, we identified fundamental differences in the trophic structure of Cambrian and modern food webs. Our results indicate that early Paleozoic community structure should be reevaluated in light of methodological advances and new data on the diversity and distribution of soft-bodied taxa.