Holomorphology, Space, and Time to Shed Light on the Evolution and Distributional Pattern of the Endemic Flowering Plants of Brazil

The disparity in species richness among clades of angiosperms is partly explained by differences in evolutionary and biogeographic processes; however, part of this imbalance remains elusive. The relationships between species diversification and key innovations, as well as the impact of clade age, are also predicted to explain such disparities. This relationship has not been examined using phylogeny-based approaches based on holomorphology, i.e., concatenated morphological and molecular datasets. Despite some large-scale evolutionary studies that have contributed to the knowledge of Brazilian flora, the evolutionary history of angiosperms endemic to Brazilian provinces has not yet been elucidated. Therefore, this study had two principal targets. First, we investigated the species richness and distribution patterns of endemic angiosperm genera. Secondly, we perform a phylogenetic analysis based on holomorphology to examine the relationship between species diversification and putative key innovations (by homology assessments) and the effects of clade age on diversification in species-rich genera. We identified the occurrence of 341 exclusive genera (45% monotypic) in 61 families. Our results indicate a positive correlation between diversification and the number of putative key innovations per order but a negative or non-existent one per family. Furthermore, our findings contradict the idea that clade age is associated with species-rich genera, challenging the notion that clade age is a determining factor in species richness. The results showed that 14 traits are closely associated with diversification, and the confluence between biotic and abiotic factors drove the diversification of species-rich genera in the Atlantic Forest, Caatinga, Cerrado, and Parana provinces.