The dichotomy of the modern bioregionalization revival

The modern bioregionalization revival is marked by an abundance of revised biogeographical classifications along with new analyses at both local and global scales. Many of these new regionalizations are based on sophisticated geospatial and species distributional models whereas others focus on the information about area relationships as inferred from the phylogenetic relationships of taxa in the areas. This results in a dichotomy between geospatial and phylogenetic approaches: areas may have the same name, but different composition and relationships. We see an opportunity to move bioregionalizations forward by proposing new regions or revising well‐known regions to reflect the advances that have been made in our understanding of phylogeny, biodiversity and Earth history during the past 50 years. Twenty‐first century biogeographers can adopt the methods of phylogenetic systematics which prescribe how taxa and their characters may be used to infer hierarchical relationships. In an analogous way, natural bioregions may be discovered by treating biotic areas as taxa and finding aggregate patterns of distributional relationships – a general areagram – as specified by phylogenies of the clades that live in those areas. We demonstrate the differences in these two approaches – general areagrams versus distributional models – in bioregionalizations and definitions of the Australian and the Neotropical regions.