Travelling through time: biogeographical patterns and insights into the areas of endemism of New World Zygophyllaceae

Spatial congruence has been the primary dimension analyzed for areas of endemism; however the role of time in shaping this congruence has been less studied. Here, we analysed the temporal dimension of areas of endemism, based on the evolutionary history of Zygophyllaceae species. We conducted an endemicity analysis using NDM/VNDM on 11 070 records representing 64 species across 12 genera. In addition, we inferred a time-calibrated phylogenetic tree to analyse the Evolutionary time of areas of endemism. We identified 18 areas of endemism and 25 endemic species. From nine consensus areas, we established five generalized areas, based on the ecoregions where they occur: Monte Desert, Dry Chaco, and Bolivian dry forest (in South America) California desert and Chihuahuan Desert (in North America). The dated phylogenetic tree indicated that endemic species originated during the Early Miocene, Late Miocene, Pliocene, and Pleistocene. Except for the Chihuahuan Desert (Late Miocene), all areas of endemism evolved asynchronously, primarily during the Early Miocene and the Pliocene during the climatic cooling and aridification periods. All endemic species currently inhabit drylands ecoregions, hence the evolution and biogeography of drylands has shaped the areas of endemism of Zygophyllaceae.