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Premise of research. Myrcia s.l. is the largest exclusively Neotropical genus of Myrtaceae, comprising about 800 species. This large genus is divided into 10 clades, most of these recently published as sections. One section, Myrcia sect. Myrcia , has 114 species distributed from Mexico to Uruguay, with species diversity centers in the Atlantic Forest, Amazon, and Cerrado. This section includes one of the most difficult to circumscribe species of the Neotropical flora, Myrcia splendens , with the same distribution as the genus and currently with almost 170 synonyms. Phylogenetic relationships and biogeographic patterns in Myrcia sect. Myrcia are examined for the first time using molecular data. Methodology. Phylogenetic inference is based on maximum likelihood and Bayesian analysis of internal transcribed spacer (nuclear), ndhF , psbA-trnH , trnL-trnF , and trnQ-rps16 (plastid) sequences obtained by sequencing a morphologically and geographically representative sample. Phylogenetic relationships, divergence time estimates, and biogeographic patterns are investigated using BEAST and BioGeoBEARS. Pivotal results. Results show that Myrcia sect. Myrcia is monophyletic as morphologically circumscribed. Internal relationships indicate morphologically distinct lineages, but the widespread and taxonomically unruly M. splendens emerges as polyphyletic. Lineages from Central America and the Amazon are sister to multiple dispersals to disparate biomes and subsequent colonization of the Cerrado. Further field and laboratory studies are necessary to understand the extreme morphological plasticity of this section, with a particular focus on improving taxonomic delimitations in M. splendens. Conclusions. This article represents the largest sample of Myrcia sect. Myrcia examined to date. The results presented here demonstrate the monophyly of the section and confirm the nonmonophyly of the widespread M. splendens , with multiple accessions emerging in independent clades from different biomes. The mean estimated age for Myrcia sect. Myrcia is 22.4 mya, and the four clades of focus in this article are estimated to have originated in the Miocene. [ABSTRACT FROM AUTHOR]

Aim: The Brazilian campo rupestre is a vegetation associated to ancient mountaintops in eastern South America, spread mainly over disjunct areas of the Espinhaço Range and the Chapada dos Veadeiros. These areas hold outstanding levels of plant diversity and endemism, but despite their uniqueness they have been neglected in recent bioregionalizations for the Neotropical region. Given their particular levels of species richness and endemism, we here test the recognition of these as distinct bioregions within the Chacoan dominion. Location: Mountaintops of eastern South America. Methods: We listed 1,748 angiosperm species endemic to the campo rupestre of the Espinhaço Range and Chapada dos Veadeiros regions, based on the data gathered from the Brazilian Flora 2020 Project. We extracted all occurrence information available from GBIF (the Global Biodiversity Information Facility) for such list and also for a polygon gathering all the study area, including information from adjacent vegetations. Data went through standard cleaning procedures and a network clustering analysis was performed to delimitate the boundaries of the new bioregions. Results: Our data strongly support the recognition of two distinct bioregions along the Espinhaço Range, but none in the Chapada dos Veadeiros. Given their high levels of endemism and singularity within the Chacoan dominion, we formalize two provinces associated to campo rupestre in the Espinhaço Range, naming them as "Chapada Diamantina" and "Southern Espinhaço" provinces. Within the latter province, three districts are also recognized, based on this and previous studies: "Diamantina Plateau", "Grão‐Mogol" and "Iron Quadrangle" districts. Main conclusions: The formalization of new and previously described bioregions highlights the campo rupestre as a vegetation harbouring outstanding levels of species richness and endemism in South America, contributing to a better understanding of biogeographical patterns in the Neotropics. Also, as we follow the International Code of Area Nomenclature as a device to standardize recognition of bioregions, this shall facilitate further biogeographical and conservation studies in these areas. Further assessments with new and revisited data are needed to enable minor scale bioregionalization within the Chacoan dominion. [ABSTRACT FROM AUTHOR]

• Tapinotaspidini broad phylogeny indicates monophyly of most genera. • Tapinotaspidini bees originated in Cerrado-like savannas in the Paleocene. • Transitions to forested areas slightly increase speciation rates. • Malpighiaceae is the ancestral host for floral oils. • Shifts to other oil plant families are possibly linked to habitat shifts. Worldwide distributed tropical savannas were established only in the Miocene, with climatic cooling and rise of C4 grasses. However, there is evidence for an earlier presence of savanna-like vegetation in southern parts of South America. Here we investigated the biogeographic history of a clade of solitary bees which have endemic groups in areas covered by savannas and other types of open vegetation as well as forested areas. We hypothesized that these bees originated in savanna-like biomes and that shifts to forested areas and floral host shifts increased species diversification along their evolutionary history. We reconstructed a comprehensive phylogeny for Tapinotaspidini bees based majorly on original DNA sequences. We then used macroevolutionary tools to estimate ancestral range area and reconstructed ancestral habitat (open versus forested) and host plant association to analyze the effects of shifts in vegetation type and flower hosts on their diversification. Tapinotaspidini bees originated in the Paleocene and in a savanna-type, Cerrado-like, which is reinforced by reconstruction of open vegetation as the most probable ancestral area, thus bringing additional evidence to a much earlier origin of this vegetation type in South America. Shifts to forested areas occurred at least three times in a period of 30 Ma and were responsible for slight increases in diversification rates. Malpighiaceae is the ancestral floral host; host broadening occurred only in the Miocene and at least in three occasions. Host shifts, i.e. from Malpighiaceae to other oil families, occurred in the Eocene and Miocene. Both host broadening and host shifts did not significantly alter diversification rates, however exploitation of other oil sources were important in occupying new habitats. The link between biomes and host plant shifts and changes in diversification rate brings us additional insights into the evolution of bees and associated flora in South America. [ABSTRACT FROM AUTHOR]