Sea level,topography and island diversity: phylogeography of the Puerto Rican Red‐eyed Coquí, Eleutherodactylus antillensis |
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Authors: | Brittany S. Barker Javier A. Rodríguez‐Robles Vani S. Aran Ashley Montoya Robert B. Waide Joseph A. Cook |
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Affiliation: | 1. Department of Biology, University of New Mexico, , Albuquerque, NM, 87131‐0001 USA;2. School of Life Sciences, University of Nevada, Las Vegas, , Las Vegas, NV, 89154‐4004 USA;3. Long Term Ecological Research Network Office, University of New Mexico, , Albuquerque, NM, 87131‐0001 USA;4. Museum of Southwestern Biology, University of New Mexico, , Albuquerque, NM, 87131‐0001 USA |
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Abstract: | Quaternary climatic oscillations caused changes in sea level that altered the size, number and degree of isolation of islands, particularly in land‐bridge archipelagoes. Elucidating the demographic effects of these oscillations increases our understanding of the role of climate change in shaping evolutionary processes in archipelagoes. The Puerto Rican Bank (PRB) (Puerto Rico and the Eastern Islands, which comprise Vieques, Culebra, the Virgin Islands and associated islets) in the eastern Caribbean Sea periodically coalesced during glaciations and fragmented during interglacial periods of the quaternary. To explore population‐level consequences of sea level changes, we studied the phylogeography of the frog Eleutherodactylus antillensis across the archipelago. We tested hypotheses encompassing vicariance and dispersal narratives by sequencing mtDNA (c. 552 bp) of 285 individuals from 58 localities, and four nuDNA introns (totalling c. 1633 bp) from 173 of these individuals. We found low support for a hypothesis of divergence of the Eastern Islands populations prior to the start of the penultimate interglacial c. 250 kya, and higher support for a hypothesis of colonization of the Eastern Islands from sources in eastern Puerto Rico during the penultimate and last glacial period, when a land bridge united the PRB. The Río Grande de Loíza Basin in eastern Puerto Rico delineates a phylogeographic break. Haplotypes shared between the PRB and St. Croix (an island c. 105 km south‐east of this archipelago) likely represent human‐mediated introductions. Our findings illustrate how varying degrees of connectivity and isolation influence the evolution of tropical island organisms. |
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Keywords: | Caribbean Sea gene flow human‐mediated introductions island biogeography isolation phylogeography Puerto Rican Bank quaternary West Indies |
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