Filogenia de Parkia R.Br. (Leguminosae, Mimosoideae) baseada em sequencias do DNA de cloroplasto

Abstract

Parkia R.Br. (Leguminosae: Mimosoideae) is a pantropical genus with about 34 species distributed in three taxonomic sections (Parkia, Platyparkia and Sphaeroparkia), defined based on the type and arrangement of the flowers in the inflorescence. In the Neotropics, the Amazon basin is the main center of taxonomic and morphological diversity of the genus containing approximately 56% of described species, the genus also occurs in paleotropicos in the forest formations of Africa, Asia, Indo-Pacific region and Madagascar. In order to test the monophyly of Parkia, assist in the elucidation of species relationships, and contribute to the ranking within Mimosoideae the phylogenetic relationships of 22 species of the genus were inferred, using Maximum Parsimony and Bayesian analyses of the trnS-trnG chloroplast marker sequences. Six morphological characters (type of inflorescence, color of fertile flowers, staminodial fringe, type of bracts, anther glands and type of fruit dehiscence) were mapped in order to investigate their evolution from the inference tree of the resulting Bayesian phylogenetic hypothesis. The monophyly of Parkia was sustained in all analyzes with high bootstrap values and posterior probability (BS 1.0, PP 1.0). Two geographically structured clades were recovered, the first clade consists of the paleotropical species and the second the neotropical species. The morphological analysis showed low levels of homoplasy and were consistent in support of some clades and subclades. In the infrageneric classification section Parkia was found not to be monophyletic, whilst the monophyly of Platyparkia and Sphaeroparkia sections were strongly supported (BS 1.0, PP 1.0). The relation of Parkia to other genera of Mimosoideae remains uncertain, but our results suggest the hypothesis of a closer relationship with Leucaena. Although our analyzes have used only a single DNA region, our results provide a first preliminary phylogeny of Parkia species based on molecular data, providing the basis for an investigation of the evolution of morphological characters, and contributing to the elucidation of its relations with other genera of Mimosoideae.