Unexpected absence of island endemics: Long-distance dispersal in higher latitude sub-Antarctic Siphonaria (Gastropoda: Euthyneura) species

• Published in: Journal of Biogeography
• Main Authors: González-Wevar, Claudio, Segovia, Nicolás, Rosenfeld, Sebastián, Ojeda, Jaime, Hüne, Mathias, Naretto, Javier, Saucède, Thomas, Brickle, Paul, Morley, Simon, Feral, Jean-Pierre, Spencer, Hamish, Poulin, Elie
• Other Authors: Universidad de Magallanes (UMAG), Instituto de Ecología y Biodiversidad (IEB), GAIA-Antártica, Laboratorio de Ecología Molecular (LEM), Biogéosciences UMR 6282 (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), School of Biological Sciences Aberdeen, University of Aberdeen, British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement IRD : UMR237-Centre National de la Recherche Scientifique (CNRS), University of Otago Dunedin, Nouvelle-Zélande
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: Antarctic circumpolar current; direct developers; long-distance dispersal; oceanic biogeography; rafting; pulmonate; Siphonaria; sub-Antarctic; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Antarctic; Southern Ocean; Kerguelen; Antarc*; Antarctique*
• Online Access: https://hal.science/hal-01698422; https://hal.science/hal-01698422/document; https://hal.science/hal-01698422/file/2018_Gonzalez-Wevar_Journal%20of%20Biogeography_pr_Unexpected%20absence%20of%20island%20endemics-%20long-distance%20dispersal%20in%20higher%20latitude%20sub-Antarctic%20Siphonaria%20%28Gastropoda,%20Euthyneura%29%20species.pdf; https://doi.org/10.1111/jbi.13174

International audience Aim: We assess biogeographical patterns, population structure and the range of species in the pulmonate genus Siphonaria across the sub‐Antarctic. We hypothesized that locally endemic cryptic species will be found across the distribution of these direct‐developing limpets in the sub‐Antarctic.Location: The sub‐Antarctic coasts of the Southern Ocean including South America, the Falkland/Malvinas, South Georgia, Kerguelen and Macquarie Islands.Methods: Multi‐locus phylogenetic reconstructions, mtDNA time‐calibrated divergence time estimations and population‐based analyses of Siphonaria populations were used at the scale of the Southern Ocean.Results: We resolve two widely distributed lineages of Siphonaria (S. lateralis and S. fuegiensis) across the sub‐Antarctic. MtDNA divergence time estimates suggest that they were separated around 4.0 Ma (3.0 to 8.0 Ma). Subsequently both species followed different evolutionary pathways across their distributions. Low levels of genetic diversity characterize the populations of both species, reflecting the role of Quaternary glacial cycles during their respective demographic histories, suggesting high levels of dispersal among geographically distant localities.Main conclusions: Siphonaria lateralis and S. fuegiensis constitute sister and broadly co‐distributed species across the sub‐Antarctic. Unexpected transoceanic similarities and low levels of genetic diversity in both these direct‐developing species imply recurrent recolonization processes through long‐distance dispersal to isolated sub‐Antarctic islands. For such groups of Southern Ocean invertebrates, rafting may be more effective for long‐distance dispersal than a free‐living planktotrophic larval stage. This biogeographical model may explain why many marine species lacking a dispersal phase exhibit broad distributions, low genetic diversity and low population structure over thousands of kilometres.