Abstract Detail

Biogeography

Pace, Matthew Charles [1], Cameron, Ken [2].

The biogeographic history of Spiranthes (Orchidaceae) reveals repeated speciation within and dispersal from the North American Geological Coastal Plain, an underappreciated biodiversity hotspot.

The biogeographic relationships of the North American flora, both within the
continent and among other regions of Earth, has been a topic of interest since European colonization. The Orchidaceae of North America, as exemplified by the genus Spiranthes, represent an excellent case study in which to examine the movement of species across the planet, the role of North American physiographic regions as arks and/or cradles areas of speciation, and the influence that North American glacial cycles may have played in cladogenesis, the isolation of disjunct populations, and speciation events. Using a calibrated molecular phylogenetic reconstruction, we estimate divergence times and likely ancestral distributional ranges for the most recent common ancestors of extant taxa. We find that contrary to long standing hypotheses, at least in the case of Spiranthes, the North American Geologic Coastal Plain has been an important center of evolution for this genus. The North American Geologic Coastal Plain has repeatedly served as an ancestral region from which clades and individual species have repeatedly dispersed and migrated, including to Eurasia, the Caribbean, and Mexico and Central America.

1 - New York Botanical Garden, Herbarium, 2900 Southern Blvd, Bronx, NY, 10458, USA
2 - University Of Wisconsin - Madison, Botany, 430 Lincoln Drive, Madison, WI, 53706, USA

Keywords:
Orchidaceae
Spiranthes
Coastal Plain
North America
Southeastern United States
BioGeoBears
disjunctions.

Presentation Type: Oral Paper
Session: 37, Biogeography II
Location: 103/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 10:45 AM
Number: 37011
Abstract ID:795
Candidate for Awards:None