| In the first chapter a study of the distribution patterns of the neotropical Vaccinieae (Ericaceae) is presented. Five areas of endemism were recovered: Central America, northern Choco, southern Choco, eastern Ecuador, and Yungas. Divergence times estimations indicate that the Andean clade of Vaccinieae migrated to South America during the Late Oligocene or Early Miocene (28.9--17.84 MA), and most of the subsequent diversification took place during the Tertiary. The Yungas was the first Andean area to be colonized, and several dispersals towards the north expanded their distribution range. Both areas of endemism and dispersal events were influenced by geological processes, such as the raise of the Andes, the western Andean Portal, and the establishment of the Central America isthmus. The second chapter is a phylogenetic analysis of Orthaea Klotzsch (Vaccinieae: Ericaceae) based on molecular and morphological data. Orthaea is polyphyletic, with members evolving independently in several lineages within the tribe Vaccinieae. Currently accepted species of Orthaea s.l. were recovered within four clades: Guiana Shield, Empedoclesia, Thibaudia p.p., and Cavendishia + Orthaea p.p. clades. Most of the Andean species of Orthaea s.l. are closely related to Cavendishia, however, relationships within this clade were not strongly supported. Combined analyses of molecular and morphological data only provided support and uncovered synapomorphies for the Guiana Shield and Empedoclesia clades. Although a core Orthaea s.s. clade was identified, no nomenclatural changes are here proposed for the remainder species of Orthaea s.l. (20 spp.), except for those previously classified in Empedoclesia, a genus that needs to be reinstated. The third chapter is a taxonomic monograph of Orthaea s.s., as delimited in the combined phylogenetic analysis mentioned above. Fifteen species were studied, including two new species (O. eteocles N. R. Salinas and O. fissiflora N. R. Salinas & Pedraza) and a new synonym ( O. glandulifera Luteyn = O. oedipus Luteyn). |
