Untangling the phylogeny of Leandra s.str. (Melastomataceae, Miconieae)

Phylogenetic studies in Melastomataceae have demonstrated the need for taxonomic rearrangements in the current classification. Nonetheless, melastomes are among the most diverse groups of plants and several cases of known artificial taxa have been observed and awaiting further resolution. The Leandra s.str. clade, with ca. 200 species, includes the majority of the taxa traditionally treated in the genus Leandra and is almost restricted to eastern Brazil. In earlier studies, some attempts have been made to infer the relationships within Leandra s.str., but the sampling was sparse and the resolution low inside the clade. Here, we attempt to provide an improved phylogenetic hypothesis for this group on which to base further studies. Specifically, we provide a comprehensive taxon sampling and attempt to infer a species tree for this group, dissecting potential noise in the phylogenetic reconstruction, such as paralogy, rogue taxa, hybridization and incomplete lineage sorting. Our data set includes 126 ingroup species (192 terminals) and four partitions (six markers). We implement the (∗)BEAST model for species tree inference and perform several simulation methods to assess model fit and to discuss potential causes for the observed patterns. Major lineages of Leandra s.str. were delineated, a strictly bifurcating species tree model seems to not account for the observed data, and hybridization is very likely an important evolutionary force in this group.