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Abstract Detail

Systematics Section/ASPT

Bell , Charles David [1], Landis, Jacob [2], SOLTIS, PAMELA S. [3], Soltis, Douglas E. [4].

Clocks and Phlox: testing hypotheses of the association of life history with diversification in Polemoniaceae.

In their classic paper on the origin and relationships of the Californian flora, Raven and Axelrod (1978) recognized Polemoniaceae as one of six exceptionally diverse plant groups in the California Floristic Province (CFP), with a high degree of endemism in this biodiversity hotspot. Raven and Axelrod hypothesized that this diversity could be explained by the evolution from a perennial to annual habit in the group, most likely in response to increasing aridity in western North America during the Miocene. Recently proposed comparative methods have helped researchers explicitly test hypotheses concerning the correlation between observed extant diversity with geological and climatological events, the evolution of novel traits, and shifts in biogeography or habitat. Here we used a fossil calibrated Bayesian relaxed clock phylogeny from a previous analysis, in combination with MEDUSA, BAMM, and BiSSE birth–death likelihood models of diversification, to evaluate the evolutionary patterns of species diversification in Polemoniaceae. We found that MEDUSA and BAMM both infer at least 2 significant increased rates of net diversification relative to background levels in the clade across several analyses.  Both of these shifts were inferred to have occurred in the Miocene, consistent with Raven and Axelrod’s hypothesis. In contrast, BiSSE analyses of correlated diversification do not find a significant correlation between rates of speciation (and net diversification) and the evolution of an annual habit. 

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1 - University Of New Orleans, Department Of Biological Sciences, 2000 Lakeshore Drive, New Orleans, LA, 70148, USA
2 - University Of Florida, Dept Of Biology, Florida Museum Of Natural History - Dickinson Hall, Museum Road And Newell Drive, Gainesville, FL, 32611, USA
3 - University Of Florida, Florida Museum Of Natural History, PO BOX 117800, Gainesville, FL, 32611-7800, USA, 352/273-1964
4 - University of Florida, Florida Museum of Natural History, Gainesville, FL, 32611

divergence time estimation

Presentation Type: Oral Paper:Papers for Sections
Session: 30
Location: Payette/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 4:30 PM
Number: 30011
Abstract ID:163
Candidate for Awards:None

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