Escalating predation on crinoids in the Devonian: negative community-level evidence

Previous morphological studies suggest that predation on stalked crinoids increased in the Devonian. However, there was no concomitant decline in the occurrence of dense, shallow-water stalked crinoid assemblages in North America from the Ordovician and Silurian to the Mississippian. The evolution of crinoid defensive adaptations may have kept pace with rising durophagy, forestalling the expected decline of crinoid communities. It is also possible that the demise of reefs after the Frasnian-Famennian mass extinction indirectly decreased predation pressure on crinoids by removing shelter for predatory fish. A third possibility is that stalked crinoid abundance was affected neither by new predators nor by the decline of reefs. □ Crinoidea, dense crinoid assemblages, Echinodermata, North America, Paleozoic, predation.