Molecular phylogeny and biogeography ofPabstiella(Pleurothallidinae: Orchidaceae) highlight the importance of the Atlantic Rainforest for speciation in the genus

Pabstiella consists of c. 130 epiphytic species in the Neotropics. We present a phylogenetic analysis based on nrITS, matK and trnH-psbA sequences from 59 species of the genus and 40 Pleurothallidinae and two Laeliinae and one Bletiinae as an outgroup, using maximum likelihood, Bayesian inference and maximum parsimony. We also performed molecular dating, biogeographical analyses and ancestral morphological character reconstruction. Our results confirm the monophyly of Pabstiella with strong support. Ten clades are inferred and are herein proposed as sections. Pabstiella originated in the Andes and the Atlantic Rainforest in the Late Miocene (c. 7.93 Mya) in an epoch when these biomes were probably connected. A main vicariance event divided an early-diverging lineage that inhabited the Andes from an Atlantic Rainforest lineage that diversified in this region during the Pliocene and Pleistocene, mainly in the Serra do Mar in south-eastern Brazil. Our findings also suggest that the Atlantic Rainforest may have played an important role in the origin of subtribe Pleurothallidinae. The morphological character reconstruction showed high levels of homoplasy, with few recognized synapomorphies associated with stems and petals. Other characters related to the habit and stems were identified as important in the evolutionary history of the genus.