Out of Antarctica: quaternary colonization of sub-Antarctic Marion Island by the limpet genus Nacella (Patellogastropoda: Nacellidae).

• Published in: Polar Biology
• Main Authors: González-Wevar, Claudio A., Chown, Steven L., Morley, Simon, Coria, Nestor, Saucède, Thomas, Poulin, Elie
• Other Authors: GAIA-Antártica, Universidad de Magallanes (UMAG), Laboratorio de Ecología Molecular (LEM), Instituto de Ecología y Biodiversidad (IEB), School of Biological Sciences Clayton, Monash University Clayton, British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Departamento de Aves Marinas, Instituto Antártico Argentino, Biogéosciences UMR 6282 (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Work supported by South African National Research Foundation Grant SNA2011110700005.
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: Biogeography; Southern Ocean; Antarctic Polar Front; Long-distance dispersal; Marion Island; Bayesian skyline plot; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Antarctic; The Antarctic; Nacella; Antarc*; Antarctica; Polar Biology
• Online Access: https://hal.science/hal-01257123; https://doi.org/10.1007/s00300-014-1620-9

13 pages International audience The distribution of the Southern Ocean nearshore marine benthic fauna is the consequence of major geologic, oceanographic, and climatic changes during the last 50 Ma. As a result, a main biogeographic principle in the Southern Ocean is the clear distinction of the Antarctic biota. The Antarctic Polar Front (APF) represents an important barrier between Antarctica and other sub-Antarctic provinces. However, the high degree of genetic affinity between populations of the Antarctic limpet Nacella concinna and its sub-Antarctic relative Nacella delesserti from Marion Island stands against this tenet. Here, we performed new phylogenetic reconstructions in Nacella with special emphasis on the relationship between N. concinna and N. delesserti. Similarly, we performed population-based analyses in N. concinna and N. delesserti to further understand the genetic legacy of the Quaternary glacial cycles. Phylogenetic reconstructions recognized N. concinna and N. delesserti as two closely but distinct monophyletic entities and therefore as valid evolutionary units. The cladogenetic process separating them occurred ~0.35 Ma and is consistent with the origin of Marion Island (~0.45 Ma). Exceptional long-distance dispersal between provinces located inside and outside the APF, rather than revealing the permeability of the Antarctic Polar Front, seems to be related to latitudinal shift in the position of the APF during coldest periods of the Quaternary. Diversity indices, neutrality tests, haplotype networks, and demographic inference analysis showed that the demography of both species exhibits a clear signal of postglacial expansion.