Abstract Detail

Biogeography

Mathews, Katherine Gould [1], Ruigrok, Michelle S. [1], Mansion, Guilhem [2].

Biogeographical Study of Diversification of Eastern North American Rose Gentians (Sabatia, Gentianaceae) on the U.S. Coastal Plain.

Sabatia (Gentianaceae) contains ca. 20 species, distributed mainly on the U. S. A. Gulf and Atlantic Coastal Plains. Our aims were to determine 1) phylogenetic relationships among Sabatia species, 2) the time and place of Sabatia’s origin and main areas of diversification, 3) relationships among sympatric species, and 4) how morphological and karyological characters evolved. We sequenced five noncoding cpDNA regions and nrITS for 30 accessions of Sabatia and its outgroups, Gyrandra and Eustoma. Parsimony, likelihood, and Bayesian phylogenetic analyses were performed. Bayesian dating was done on a reduced-taxon, combined molecular dataset. The maximum clade credibility chronogram was used for ancestral area reconstruction and character optimization. Correlations between distributional, environmental and phylogenetic matrices were tested with spatial analyses. Phylogenetic analyses reveal that a Sabatia + Gyrandra clade diverged in the late Middle Miocene, with Sabatia subsequently splitting into western and eastern Gulf Coast clades during the early Late Miocene. Further diversification took place in the Late Miocene-Pliocene, with more recent range expansion. Pliocene glacial and interglacial periods could have triggered range contraction or expansion, associated with chromosomal changes. Closely related species of Sabatia tend to share both distributions and habitat types. Character optimization showed potential synapomorphies for a polymerous clade and a white-flowered clade.

1 - Western Carolina University, Biology Department, 132 Natural Science Bldg, Cullowhee, NC, 28723, United States
2 - Zürich, Switzerland

Keywords:
aneuploidy
coastal plain
Floral form and size
molecular dating
S-DIVA.

Presentation Type: Oral Paper:Papers for Topics
Session: 72
Location: Salon 3/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 2:45 PM
Number: 72006
Abstract ID:1138
Candidate for Awards:None