The seasonally dry tropics stand out among tropical biomes for their distinctive plant communities as assessed along environmental, functional, structural, and phylogenetic axes. The distinctiveness of dry tropical forest species is driven particularly by high niche conservatism and strong spatial turnover compared to other tropical biomes. The legumes, as the pre-eminent dry tropical forest family by a margin of nearly two-fold (many of them mimosoid legumes), can be safely claimed as an archetypal group for the study of tropical dry forest. While only marginally present in cold to warm temperate areas compared to subfamily Papilionoideae, the other major legume radiation outside of moist tropical regions, they are some of the most prominent legumes of the semi-arid tropics and subtropics globally, concentrated between 36°N and 36°S and dominant in savannah biomes, particularly in Africa and Australia. To better understand global patterns of diversity and endemism in the dry tropics, here we determine centers of species richness (SR), relative phylogenetic diversity (RPD) and paleo- and neo-endemism in the mimosoid clade. We also use distance methods to regionalize phylogenetic diversity and understand spatial breaks in phylogenetic diversity and the relationships of recognized diversity centers in terms of shared lineage diversity. Finally, because mimosoid legumes are one of the richest clear examples of nodule loss, important to interpreting the drivers of diazotrophic symbiotic strategies, we map the distribution of mimosoids lacking RNS (root nodule symbiosis).  Using data from the NitFix sequencing iniative, we built a phylogenetic tree covering 1313 species and high-quality species distribution models covering 1128 species. Centers of significant RPD and endemism were identified using a randomization approach, the latter using CANAPE. Phylogenetic regionalization used a distance-based phylogenetic beta-diversity approach. RNS species were identified using a recent authoritative RNS database, also assembled through the NitFix iniative.   We recovered nine distinct SR hotspots, which are partly incongruent with centers of RPD and phylogenetic endemism. Regionalization of phylogenetic diversity showed partial congruence with previous legume biome classifications but failed across continents to recover a clear split between tropical dry forest and scrub biomes. This suggests that scrub and dry forest mimosoid communities, while distinct, are assembled from closely related lineages. Lineages lacking RNS are distributed in hotspots in Africa and the Americas, and specifically associated with relatively moist tropical environments with low temperature seasonality and high nitrogen.