Abstract Detail

Biogeography

Nieto-Blazquez, Maria Esther [1], Antonelli, Alexandre [2], Roncal, Julissa [3].

Historical Biogeography of endemic seed plant genera in the Caribbean: did GAARlandia play a role?

The aim of this study was to better understand the historical assembly and evolution of endemic seed plant genera in the Caribbean, by first determining divergence times of endemic genera to test whether the GAARlandia landbridge played a role in the archipelago colonization, and second by testing South America as the main colonization source as expected by the position of landmasses and recent evidence of an asymmetrical biotic interchange. To accomplish this we gathered DNA sequences from four loci (18S rDNA, atpB, matK and rbcL) for 610 species, including 41 seed plant genera endemic to the Caribbean (out of 180 in total). We reconstructed a dated molecular phylogeny using Bayesian inference and ten calibrations. To estimate the range of the ancestors of endemic genera we performed a model selection between a null and a more complex biogeographical model that included timeframes based on geological information and dispersal probabilities among regions. Divergence times for endemic genera ranged from Early Eocene (53.1 Ma) to Late Pliocene (3.4 Ma). Only the origin of three endemic genera occurred within the GAARlandia timeframe (35 to 33 Mya), whose ancestors derived from the Old World. Our data set shows that over half of the endemic genera and sister taxa had their ancestors distributed in the Antilles. Central America, South America and the Old World ancestors contribute almost equally as sources of colonization for the rest of endemic genera. In contrast with recent patterns shown for vertebrates and other organisms, GAARlandia did not act as a main colonization route for plants between South America and the Antilles. Divergence of endemic genera occurred mostly during the Miocene, i.e. after the proposed existence of GAARlandia. According to our expectations, the origin of endemic genera exhibited a mixed pattern of colonization from continental masses and in situ radiations within the islands, where South America did not play a particular major role as source of island colonization. A species-level synthesis on Caribbean plant dispersal will be required to reveal finer-scale patterns and mechanisms

1 - Memorial University of Newfoundland, Biology, Elizabeth Ave, St.John´s, NL, A1B 3X9, Canada
2 - University of Gothenburg, Department of Biological and Environmental Sciences, Gothenburg Botanical Garden, Carl Skottsbergs Gata 22A A, 413 19, Gothenburg, PO Box 461, 405 30, Sweden
3 - Memorial University Of Newfoundland, 232 Elizabeth Avenue, St. John\'s, N/A, A1B 3X9, Canada

Keywords:
Antilles
Cenozoic
colonization
dispersal
island biogeography
West Indies.

Presentation Type: Oral Paper
Session: 13, Biogeography
Location: Sundance 3/Omni Hotel
Date: Monday, June 26th, 2017
Time: 1:45 PM
Number: 13002
Abstract ID:138
Candidate for Awards:None