Mapping Devonian Bioregions: Scale and Synonymy

Devonian bioregions have been consistently used since their formalisation by AJ Boucot in the 1960’s to describe the biotic and environmental conditions of the Devonian seas. Bioregions aggregate information from biofacies, lithology, and occurrence data and are a useful framework for examining the generalised spatial signatures of diversity and dispersal. The characterisation of the Devonian bioregions has been shown to be unstable both in terms of their ability to be consistently recovered using aggregated generic profiles, and by clade specific (e.g. exclusively trilobites) treatments. This instability is, in part, due to an attempt to scale across the entire Devonian despite significant turnover and global events, and inconsistent ‘area taxonomy’. In this study, I highlight the difference in approach between bioregionalisations based on and lithology and co-occurrence (modelled after Boucot) and those that integrate global reconstructions of the Devonian Earth using tectonic and climate models.