Abstract Detail

Biogeography

Jantzen, Johanna [1], Soltis, Douglas [2], Soltis, Pamela [3].

Biogeography of Tibouchina s.s.: identifying the origins of cerrado and campos rupestres plant diversity.

Although the cerrado and campos rupestres of Brazil are recognized as biodiversity hotspots, the evolutionary origins of the flora of these ecoregions are not well understood. Tibouchina sensu stricto (Melastomataceae) is a clade of 30 species that has high species diversity and endemism in both the cerrado and campos rupestres, with some members of the clade occupying other open savanna-like habitats across northern and central South America, including the tepuis of the Guiana Shield. To identify the biogeographic origins and drivers of diversification in this clade, we reconstructed a well-sampled phylogeny using phylogenomic methods. Using BioGeoBears, we reconstructed ancestral biogeographic regions and determined the ancestral area for the clade. A clade of two widespread species is sister to a large clade of all other species of Tibouchina s.s. This clade of 28 species consists, in turn, of a northern clade and a southern clade. The phylogeny was dated to identify geological and climatic events that correspond with divergence events. By reconstructing ancestral ecoregions on the phylogeny, we also determined that species of the campos rupestres represent separate migration-speciation events from cerrado or savanna ancestors. These results indicate that the cerrado and campos rupestres consist of recently formed vegetation communities and that the highly diverse flora of the campos rupestres is the result of repeated transitions from the cerrado to the campos rupestres. We found that the species narrowly endemic to the campos rupestres are nested within clades of more widespread cerrado species, while the narrow endemics found in the tepuis of the Guiana Shield are more closely related to each other than to the more widespread species of northern South America. Understanding the evolution of Tibouchina s.s. provides insight into the geographic origins of the flora of both the cerrado and campos rupestres, as well as the tepui flora of the Guiana Shield.

1 - University Of Florida, Biology, Dickinson Hall, 1659 Museum Road, Gainesville, FL, 32611, United States
2 - University of Florida, Florida Museum of Natural History, PO Box 117800, Gainesville, FL, 32611, USA
3 - University Of Florida, Florida Museum Of Natural History, Po Box 117800, Gainesville, FL, 32611, United States

Keywords:
biogeography
Cerrado
Campos rupestres
Tibouchina
Melastomataceae
Tepui.

Presentation Type: Poster
Session: P, Biogeography Posters
Location: Arizona Ballroom/Starr Pass
Date: Monday, July 29th, 2019
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PBG008
Abstract ID:570
Candidate for Awards:None