Abstract Detail

Biogeography

Gallaher, Timothy [1], Keeley, Sterling [2].

An Australian origin for the Pandanus tectorius complex: a model for understanding speciation in ocean-dispersed Angiosperms.

The Pandanus tectorius complex is the most widespread lineage in the Pandanaceae with species inhabiting coastal areas from Western Africa to Eastern Polynesia. These plants disperse over long distances via floating fruit and several key innovations, including a multi-seeded propagule and facultative apomixis, appear to have contributed to the geographic success of the group. The number of species in the complex however has long been a subject of debate. Over 300 taxa have been ascribed to the complex; however, most have been synonymized with just two widespread species. A poor understanding of factors that contribute to the isolation of populations of ocean-dispersed angiosperms and the subsequent formation of new species has contributed to the taxonomic problem. A Bayesian phylogeny was constructed using chloroplast and nuclear markers with representative species from all Pandanus subgenera and numerous putative taxa from the P. tectorius complex. The complex is nested within a clade of 15 Australian species of subg. Pandanus. This clade initially diverged into two geographically separated adaptive radiations; one in the Northern Territory and another in coastal north Queensland. The P. tectorius complex originated in the Pliocene as part of the north Queensland radiation, and has spread and diversified across the Indo-Pacific from coastal Africa to Hawaii. Mechanisms promoting divergence within the group include isolation driven by the patterns of ocean-currents and secondary dispersal away from coastal populations mediated by frugivory.

Broader Impacts:

1 - University of Hawaii at Manoa, Botany, 3190 Maile Way, Honolulu, HI, 96822, USA
2 - University of Hawaii, DEPT. BOTANY, 3190 MAILE WAY, ROOM 101, Honolulu, HI, 96822-2279, USA

Keywords:
Adaptive Radiation
Australia
BEAST
Long Distance Dispersal
Ocean-Dispersal
Pacific Biogeography
Pandanus tectorius complex.

Presentation Type: Oral Paper:Papers for Topics
Session: 38
Location: Marlborough A/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 8:45 AM
Number: 38002
Abstract ID:217
Candidate for Awards:George R. Cooley Award