PALEOZOIC PELAGIC AND BENTHOPELAGIC MACROECOLOGY: WAS THERE A DEVONIAN NEKTON REVOLUTION?

It has been suggested that nektic ecologies arose suddenly during the Devonian as a result of benthic crowding. We use the Paleobiology Database, Sepkoski’s Compendium of Fossil Marine Animal Genera, and other stratigraphic diversity datasets to describe Paleozoic benthopelagic and pelagic macroecology (motility and zonation) at fine taxonomic resolution. We demonstrate that the proposed Devonian Nekton Revolution (DNR) was an artifact of inadequate taxon sampling and overly generalized life mode assessments. The relative proportion of nektic metazoans to demersal and planktic ones appears fairly stable throughout the Paleozoic. Although a clear mid-paleozoic increase in eunekton can be observed, these diversifications began earlier, proceeded more gradually, and were less comprehensive than initially envisioned.