The importance of the Mexican taxa of Asteraceae in the family phylogeny

Asteraceae is the largest plant family in Mexico with about 417 genera and 3113 species, and with more than 60% of them being endemic. Phylogenetic relationships at subfamily and tribal levels have been previously resolved employing both nuclear and plastid molecular markers. However, Asteraceae species native to Mexico have been underrepresented in such phylogenies. To tackle this issue, the taxon sampling of this study included 90 Asteraceae species native to Mexico, four species from the Caribbean, 119 previously sequenced species, and six outgroups. With this sampling, all the Asteraceae subfamilies and all of the tribes recognized to date are represented. The analyzed dataset consisted of eleven chloroplast markers (atpB, matK, ndhC, ndhD, ndhF, ndhI, ndhJ, ndhK, rbcL, trnL-trnF, and 23S-trnA). We present two phylogenetic reconstructions obtained by maximum likelihood and pseudocoalescent methods. Besides, we present a time-calibrated phylogeny, which is used to infer the best configuration of diversification rate shifts. Our results show that Mexican species are distributed mainly in the subfamily Asteroideae (80 species), followed by Cichorioideae (6 species), Carduoideae (2 species), and Mutisioideae (2 species). Four net diversification rate shifts were found: One near the base of the tree and four within Asteroideae subfamily. Our extended sampling of the family with the representation of native species to Mexico allowed us to identify important events in the evolutionary history of the family.