Abstract Detail

Biogeography

Hall, Jocelyn C. [1], Cardinal-McTeague, Warren [2], Sytsma, Kenneth J. [3].

Biogeographical analyses of the core Brassicales reveal a lineage driven by long distance dispersal.

Brassicales is a diverse lineage perhaps most famous because it houses Brassicaceae and, its premier member, Arabidopsis thaliana. However, the order has been overlooked as a promising system to investigate patterns of disjunct distributions and diversification rates. We analyzed sequence data from 5 gene regions (>8000 bp) across 150 taxa to: (1) provide robust support for relationships within the order, (2) estimate ages for major lineages within the order including Brassicaceae and Arabidopsis based on greater sampling across order and previously overlooked fossil evidence, (3) examine biogeographical ancestral area reconstructions and disjunct distributions in BioGeoBEARS, and (4) determine where shifts in species diversification occur. Core Brassicales diverged at 68.5 Ma (HPD =75.6-62.0), most likely in North America, followed by many transitions into Old World and Asia. This estimated age combined with fossil evidence, indicates that some New World clades embedded amongst Old World relatives (e.g., New World capparoids) are the result of different long distance dispersal events. Based on these analyses, the Brassicaceae crown group diverged in Europe/Northern Africa in the Eocene, circa 43.4 Ma (HPD = 46.6-40.3) and Arabidopsis separated from close congeners circa 16 Ma. These ages fall between divergent dates that were previously published, suggesting we are slowly converging on a robust estimate for the family. Three significant shifts is species diversification are seen in the order: (1) 58 Ma at the crown of Brassicaceae, Cleomaceae and Capparaceae, (2) 38 Ma at the crown of Resedaceae + Stixis clade, and (3) 38 Ma at the crown of core Brassicaceae.

1 - University of Alberta, Biological Sciences, CW 405 Biological Sciences Building, Edmonton, Alberta, T6G 2E9, Canada
2 - Canadian Museum of Nature, Research & Collections, PO Box 3443, Station D, Ottawa, ON, K1P 6P4, Canada
3 - University Of Wisconsin, Department Of Botany, Birge Hall, 430 Lincoln Drive, Madison, WI, 53706, USA

Keywords:
Brassicaceae
Brassicales
Cleomaceae
biogeography
BioGeoBEARS
BAMM diversification.

Presentation Type: Oral Paper:Papers for Topics
Session: 59
Location: Salon 3/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 10:45 AM
Number: 59010
Abstract ID:718
Candidate for Awards:None