Abstract Detail

Macroevolution

Larson-Johnson, Kathryn [1].

Phylogenetic investigation of the complex evolutionary history of dispersal mode across living and fossil Fagales and its impact on extant biogeography and diversity.

As a primary determinant of spatial structure in angiosperm populations, fruit dispersal may impact large-scale ecological and evolutionary processes. Essential to understanding these mechanisms is an accurate reconstruction of dispersal mode over the entire history of an angiosperm lineage. A total-evidence phylogeny was reconstructed using a Bayesian approach for most fossil fruit and all extant genera in Fagales over its c. 95 million year history. This phylogeny—the largest of its kind to include plant fossils—was used to reconstruct an evolutionary history directly informed by fossil morphologies and to assess relationships among dispersal mode, biogeographic range size, and diversification rate. Reconstructions of dispersal mode indicate unassisted dispersal at the base of Fagales with four subsequent transitions to wind dispersal and seven to biotic dispersal. Phylogenetic integration of fossils proved crucial to understanding these patterns, many fewer transitions were reconstructed when only extant genera were included. The complexity of dispersal mode evolutionary patterns further increased when more specialized behaviors were considered, with fluttering, gliding, autorotating, and scatter-hoarding each evolving multiple times across the order. Preliminary biogeographic analyses of all extant fagalean species indicate larger range sizes of biotically dispersed groups as well as a latitudinal trend in both dispersal mode and geographic range size, with biotic dispersal and smaller ranges more common at lower latitudes. When analyzing extant members, biotically dispersed lineages had significantly higher diversification rates than abiotically dispersed lineages, with rates more than three times faster in biotically dispersed groups. Although these results indicate that transitions in dispersal mode are an important aspect to understanding diversification in Fagales, these transitions alone cannot explain all detected diversification rate shifts across Fagales.

1 - Stanford University, School of Earth, Energy, and Environmental Sciences, 397 Panama Mall, Stanford, CA, 94305, USA

Keywords:
Phylogeny
Total Evidence
fossil
seed dispersal
biogeography
Diversification
angiosperm.

Presentation Type: Oral Paper:Papers for Topics
Session: 3
Location: Salon 3/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 11:15 AM
Number: 3013
Abstract ID:1013
Candidate for Awards:None