A Phylogenetic Analysis of Lychnophorinae (Asteraceae: Vernonieae) Based on Molecular and Morphological Data

Abstract—

The subtribe Lychnophorinae (Asteraceae: Vernonieae) comprises approximately 100 species and 18 genera distributed mostly in the Cerrado Domain of the Brazilian Central Plateau. Phylogenetic analyses of Lychnophorinae based on four molecular regions (ETS, ITS, ndhF, rpl32-trnL) and a morphological dataset were performed, aiming to delimit monophyletic genera, to confirm or refute the generic assignment of several species, to achieve a better understanding of the relationships between the genera, and to identify morphological characters and synapomorphies for major clades within the subtribe. Our analyses recovered several clades that represent currently recognized genera or genera that have been recognized in the past. All clades recovered are characterized by a combination of morphological characters. However, Lychnophora (35 species), the richest genus of the subtribe, emerged as polyphyletic. Albertinia, Blanchetia and Gorceixia were the first lineages to diversify, whereas Eremanthus plus Lychnophora sensu stricto emerged as the most derived clade. Relationships among other clades remained partially unresolved. Some incongruence in the placement of species of Eremanthus, Paralychnophora, and Piptolepis in the nuclear and chloroplast phylogenies provided additional evidence for the occurrence of two putative intergeneric hybrids in the wild. Biogeographic reconstruction suggests that the diversification and expansion range of most Lychnophorinae clades in the campos rupestres, from an ancestor in tropical seasonl forests, occurred previously to the conquest of the cerrado s. s. areas performed by only a few clades.