DIVERSIFICATION OF Stigmaphyllon A. JUSS. (MALPIGHIACEAE) IN THE ATLANTIC FOREST Rafael Felipe de Almeida1*, Uiara Catharina Soares e Silva2 & Cássio van den Berg1 1 Universidade Estadual de Feira de Santana, Departamento de Ciências Biológicas, Programa de Pós-Graduação em Botânica, Av. Transnordestina s/n, Novo Horizonte, 44036-900, Feira de Santana, Bahia, Brasil. [email protected] 2 Instituto Tecnológico Vale - Desenvolvimento Sustentável, Rua Boaventura da Silva, 955, Umarizal, 66055-090, Belém, Pará, Brasil. Stigmaphyllon A. Juss. is the only genus of Malpighiaceae to occupy the tropics worldwide, comprising ca. 120 species commonly found in Rain Forests. The genus is currently divided into two subgenera based on morphological and molecular evidence. In previous molecular phylogenies for the family, Stigmaphyllon was recovered as monophyletic, but its type species has never been sampled. Thus, in order to test the monophyly of Stigmaphyllon and understand its diversification in the Atlantic Forest, we present a dated molecular phylogeny for it based on two nuclear (ETS and PHYC) markers. A total of 25 species of Stigmaphyllon were sampled, including its type specimen, and seven species from outgroups Banisteriopsis (4), Bronwenia (1) Diplopterys (1), and Peixotoa (1). A matrix with a combined nuclear dataset was elaborated and analyzed using the principle of Maximum Parsimony (MP) and Bayesian Inference (BI). Stigmaphyllon was recovered as monophyletic and well supported by BI and MP analyses, and its ancestor diverged ca. 24 ma. Nine main lineages were recovered in the genus as moderately to highly supported by both analysis: clade 1 (15 ma) is represented by two species from rocky fields, Seasonally Dry Tropical Forest (SDTF), and restingas from eastern Brazil; clade 2 (12 ma) is represented by three species commonly found in SDTF and restingas in eastern Brazil; clade 3 (13 ma) is represented by two species of the paleotropic subgenus Ryssopterys and a single species from neotropical restingas of subgenus Stigmaphyllon; clade 4 (6 ma) is represented by an Amazonian and an Atlantic Forest species; clade 5 (14 ma) is represented by a single early diverging species from savannas of Central Brazil; clade 6 (7 ma) is represented by four species endemic to southern and central Atlantic Forest; clade 7 (0.5 ma) is represented by two Amazonian species; clade 8 (10 ma) is represented by a single species endemic to the SDTF; and clade 9 (9.5 ma) is represented by seven species endemic to the Atlantic Forest. We demonstrate the paraphyly of S. subg. Stigmaphyllon, and show that the genus colonized the Atlantic Forest at least three times at ca. 24 ma, 14.5 ma and 9.5 ma. Our results indicate that once additional species and genes are sampled, a new infrageneric classification in the genus will be necessary, as well as a comprehensive biogeographic study in order to understand how Stigmaphyllon conquered the tropics (Capes, CNPq, Fapesb, Smithsonian Institution). Keywords: Biogeography, Evolution, Malpighiales, Neotropical flora, Phylogenetics, Taxonomy. .