Sistemática e Biogeografia de Parkia (Leguminosae, Caesalpinoideae, clado mimosoide)

Abstract

Parkia R.Br. (Leguminosae, Caesalpinioideae, mimosoid clade) is a pantropical genus with approximately 35 species recognized in three taxonomic sections (Parkia, Platyparkia and Sphaeroparkia), defined based on the type and arrangement of the flowers in their inflorescences. With a high degree of endemism, the species of the genus have diversified into tropical forests and savannas in South and Central America, Africa, Madagascar and the Indo-Pacific region. In this study, phylogenetic analyses dated by fossil calibration (Maximum Likelihood and Bayesian Inference) and biogeographic analyses (BioGeoBEARS) were performed using chloroplast DNA (matK, trnL, psbA-trnH and rps16-trnQ) and nuclear (ITS/18S/26S) data in order to test the monophyly of Parkia and its three infrageneric groups; estimate the times of divergence of their lineages and what factors may have influenced their diversification; infer the geographical origin and investigate the evolution of its floral morphology and its pollination systems. Our results support the monophyly of the genus, the sections Sphaeroparkia and Platyparkia are monophyletic; the section Parkia is recovered as paraphyletic. Fossil-calibrated biogeographic and bayesian analyses estimate Parkia origin approximately 18.49 Ma in the Neotropical region. Capitulum evolution shows a transition from a specialized structure to a simpler structure. Chiropterophily is probably ancestral and entomophily is derived.