Create your own conference schedule! Click here for full instructions

Abstract Detail


Roncal, Julissa [1], Couderc, Marie [2], Baby, Patrice [3], Kahn, Francis [4], Millan, Betty [4], Meerow, Alan [5], Pintaud, Jean-Christophe [2].

Contrasting Andean geodynamics drive evolution of lowland taxa in western Amazonia.

The Nazca plate subduction and the eastward Andean orogenic wedge propagation in western Amazonia caused the retreat of the aquatic Pebas system and the formation of arches or ridges that influenced the modern configuration of the upper Amazon drainage. These palaeogeographical changes in topographic relief and river dynamics are widely accepted to have influenced the diversification of biota through vicariance. We used a palm lineage of 15 species (Astrocaryum sect. Huicungo : Arecaceae) restricted to western Amazonia to test this hypothesis. We present a phylogeographic analyses based on the polymorphism at five chloroplast and two nuclear non-coding DNA fragments, supplemented with geological dates for western Amazonian elements. We found a phylogeographic break at ca. 5°S in Peruvian Amazonia, and evidence of past ancestral population expansion into three western Amazonian regions with no clear genetic differentiation imposed by river barriers or arches. The two main clades that defined the geographic break diversified ca. 6.7 and 5.6 million years ago (Mya) in the Subandean foothills of central Peru, and in the subsiding northern Amazonian foreland basin, respectively. These two regions present contrasting geological activities. The Subandean foothills developed from Late Miocene times (9 ±2 Mya) with a significant exhumation related to tectonic uplift. To the north, the transcontinental modern drainage and sedimentation of the northern Amazonian foreland basin are directly related to the Fitzcarrald arch uplift, which started around 5 Mya. Our results support the role of dispersal and geological selection forces in the historical assembly of lowland western Amazonian forests.

Log in to add this item to your schedule

1 - Memorial University of Newfoundland, Biology, 232 Elizabeth Avenue, St. John's, NL, A1B 3X9, Canada
2 - Institut de Recherche pour le Development, UMR DIADE, 911 Av. Agropolis, BP 64501, Montpellier, 34394, France
3 - Institut de Recherche pour le Development, Convenio IRD-PERUPETRO, Lima, Peru
4 - Universidad Nacional Mayor de San Marcos, Museum of Natural History, Avda. Arenales 1256 Jess Mara, Lima, Peru
5 - U.S. Department of Agriculture, USDA-ARS-SHRS, National Germplasm Repository, 13601 Old Cutler Road, Miami, 33158, USA

nothern Amazonian foreland basin
subandean foothills
diversification time

Presentation Type: Oral Paper:Papers for Topics
Session: 3
Location: Salmon/Boise Centre
Date: Monday, July 28th, 2014
Time: 9:15 AM
Number: 3006
Abstract ID:97
Candidate for Awards:None

Copyright 2000-2013, Botanical Society of America. All rights reserved