Article

Crossing the impassable: genetic connections in 20 reef fishes across the eastern Pacific barrier.

Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Panama.
Proceedings of the Royal Society B: Biological Sciences (Impact Factor: 5.29). 10/2006; 273(1598):2201-8. DOI: 10.1098/rspb.2006.3543
Source: PubMed

ABSTRACT The 'impassable' Eastern Pacific Barrier (EPB), ca 5000 km of deep water separating the eastern from the central Pacific, is the World's widest marine biogeographic barrier. Sequencing of mitochondrial DNA in 20 reef fish morphospecies encountered on both sides of the barrier revealed cryptic speciation in two. Among the other 18 species only two showed significant differentiation (as revealed by haplotype networks and FST statistics) between the eastern and the central Pacific. Coalescence analyses indicated that genetic similarity in the 18 truly transpacific species resulted from different combinations of ages of most recent invasion and of levels of recurrent gene flow, with estimated times of initial separation ranging from approximately 30000 to 1 Myr (ago). There is no suggestion of simultaneous interruptions of gene flow among the species. Migration across the EPB was previously thought to be exclusively eastward, but our evidence showed two invasions from east to west and eight cases in which subsequent gene flow possibly proceeded in the same direction. Thus, the EPB is sporadically permeable to propagules originating on either side.

Full-text

Available from: Harilaos Lessios, May 12, 2014
0 Followers
 · 
81 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: AimTo discover and evaluate potential dispersal barriers across the Indo-West Pacific Ocean and to develop spatially explicit hypotheses regarding the location of barriers and their capacity to filter taxa. Additionally, to compare model predictions with previously described barriers and build a more thorough understanding of the region's biogeographic patterns.LocationThe reefs of the Indo-West Pacific Ocean, from 100 to 170°E and from 30°N to 30°S.MethodsA biophysical larval dispersal model was used to quantify over 800,000 dispersal kernels by simulating 99 model taxa. Spatial analysis was used to map emergent patterns of potential multispecies population connectivity and predict geographic locations and strength of concordant dispersal barriers across the seascape.ResultsAlthough individual taxa varied in their predicted fine-scale population connectivity, there was consistency in the location of dispersal barriers. Across all trait combinations, reproductive output (fecundity and density of reproductive adults), reproductive strategy (spawning phenology) and the length of the larval dispersal phase determined the strength of barriers across the seascape. More than 80% of the previously described marine boundaries in the region were predicted to restrict the dispersal of at least 10% of the simulated taxa. The location and strength of many additional multitaxa barriers were described at scales <200 km.Main conclusionsThe geographic structure of many previously described multispecies barriers across the Indo-West Pacific were predicted with the biophysical dispersal model and spatial analysis. The permeability of individual dispersal barriers was primarily determined by reproductive output, spawning phenology and the length of the pelagic larval stage. Across all dispersal barriers analysed, Euclidean distance explained up to 49% of the variation in barrier strength.
    Diversity and Distributions 02/2015; 21(4). DOI:10.1111/ddi.12307 · 5.47 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Biodiversity patterns across the marine tropics have intrigued evolutionary biologists and ecologists alike. Tropical coral reefs host 1/3 of all marine species of fish on 0.1% of the ocean’s surface.Yet our understanding of howmechanistic processes have underpinned the generation of this diversity is limited. However, it has become clear that the biogeographic history of the marine tropics has played an important role in shaping the diversity of tropical reef fishes we see today. In the last decade, molecular phylogenies and age estimation techniques have provided a temporal framework in which the ancestral biogeographic origins of reef fish lineages have been inferred, but few have included fully sampled phylogenies or made inferences at a global scale. We are currently at a point where newsequencing technologies are accelerating the reconstruction and the resolution of the FishTree of Life. How will a complete phylogeny of fishes benefit the study of biodiversity in the tropics? Here, I review the literature concerning the evolutionary history of reef- associated fishes from a biogeographic perspective. I summarize the major biogeographic and climatic events over the last 65 million years that have regionalized the tropical marine belt and what effect they have had on the molecular record of fishes and global biodiversity patterns. By examining recent phylogenetic trees of major reef associated groups, I identify gaps to be filled in order to obtain a clearer picture of the origins of coral reef fish assemblages. Finally, I discuss questions that remain to be answered and newapproaches to uncover the mechanistic processes that underpin the evolution of biodiversity on coral reefs.
    Frontiers in Genetics 11/2014; 5(November):1-15. DOI:10.3389/fgene.2014.00394
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A fish from the Balistidae family was collected off Michoacán, Mexico. The fish was identified as Sufflamen fraenatum (Balistidae) based on its taxonomic and genetic traits. This finding confirms the presence of this species in the Mexican Pacific. The species has not been collected since 1897; for this reason, its record and distribution in the Mexican coast has been considered as in doubt by several authors.