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Abstract Detail


Biogeography

Zhou, Linlin [1], Su, Yvonne C.F. [1], Saunders, Richard [1].

Out of Africa: alternative African-Asian plant dispersal routes in the Tertiary reassessed using Uvaria (Annonaceae).

Uvaria L. (Annonaceae) is a species-rich palaeotropical genus of woody climbers and scandent shrubs. Previous phylogenetic reconstructions of this genus show a very clear correlation with geographical origin with species from Africa basal to those from Asia. In the present study, divergence times of this genus are estimated by analysis of the DNA sequences of four regions (matK, psbA-trnH spacer, rbcL and trnL-F) from 59 Uvaria species (sampled throughout Africa, Asia and Australia), and 77 outgroup species using an uncorrelated lognormal (UCLD) relaxed molecular clock in BEAST. The ancestral area of Uvaria and subsequent dispersal routes were inferred using Dispersal-Vicariance Analysis (DIVA). Uvaria is estimated to have originated at ca. 31.33 Mya (95% HPD: 38.6024.72 Mya) in Tropical West-Central Africa and subsequently dispersed into Asia between ca. 21.02 Mya (95% HPD: 26.0616.35 Mya) and ca. 15.90 Mya (95% HPD: 20.1712.09 Mya). By combining the origin and dispersal events with their corresponding ages, alternative hypotheses on African-Asian plant dispersal routes in the Tertiary are reassessed. Eocene dispersal via the boreotropical forests of southern Europe and tectonic rafting on India can be discounted as possible explanations due to incongruence with the divergence time estimations. Two alternative possibilities are suggested: dispersal via the boreotropical forests of southern Europe or Arabia during the Miocene thermal maximum; and long-distance (transoceanic) dispersal.

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1 - The University of Hong Kong, School of Biological Sciences, Division of Ecology & Biodiversity, 3S-17, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong

Keywords:
Ancestral area
Biogeography
boreotropic hypothesis
diversification rates
Indian rafting
long distance dispersal
molecular dating.

Presentation Type: Oral Paper:Papers for Topics
Session: 3
Location: 551A/Convention Center
Date: Monday, August 2nd, 2010
Time: 10:45 AM
Number: 3011
Abstract ID:315


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