Molecular divergence between Iridaea cordata (Turner) Bory de Saint-Vincent from the Antarctic Peninsula and the Magellan Region

• Published in: Journal of Applied Phycology
• Main Authors: Ocaranza-Barrera, Paula, González-Wevar, Claudio A., Guillemin, Marie-Laure, Mansilla, Andrés, Rosenfeld, Sebastián
• Other Authors: Laboratorio de Ecología de Macroalgas Antárticas y Sub antárticas (LEMAS), Universidad de Magallanes (UMAG), Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Instituto de Ecología y Biodiversidad (IEB), Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Biologie évolutive et écologie des algues = Evolutionary Biology and Ecology of Algae (EBEA), Pontificia Universidad Católica de Chile (UC)-Sorbonne Université (SU)-Universidad Austral de Chile-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff = Roscoff Marine Station (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: Southern Ocean; Rhodophyte; biogeography; Antarctic Circumpolar Current; cryptic speciation; vicariance; [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics; [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE]; Antarctic; The Antarctic; Antarctic Peninsula; Drake Passage; Bory; Saint-Vincent; Antarc*
• Online Access: https://hal.science/hal-04058282; https://hal.science/hal-04058282/document; https://hal.science/hal-04058282/file/Ocaranza-Barrera_2019_J.App.Phycology.pdf; https://doi.org/10.1007/s10811-018-1656-2

The distribution of the Southern Ocean (SO) biota is the result of major geologic, oceanographic and climate changes during the last 50 million years (Ma). Several groups of marine benthic organisms exhibit marked taxonomic similarities between Antarctic Peninsula and southern South America where families, genera and even species are currently co-distributed in these continents. Several species of macroalgae such as Gigartina skottsbergii, Plocamium cartilagineum, Iridaea cordata, are currently found at both sides of the Drake Passage. Advances in molecular techniques have allowed to determine their phylogenetic relationships and level of divergence between populations from these continents in order to determine whether they constitute separate evolutionary units. In this study we determine whether Iridaea cordata represents the same evolutionary unit in southern South America and the Antarctic Peninsula or if populations at both sides of the Drake Passage, separated by the Antarctic Polar Front (APF), represent putative cryptic species. According to our results, I. cordata populations from Antarctic Peninsula and South America are clearly distinguishable evolutionary units with a 8.31% and a 3.17% mtDNA and cpDNA molecular divergence, respectively. The separation between Antarctic and South American populations of I. cordata occurred at the end of the Miocene between 5 Ma (rbcL) and 9 Ma (COI-5P). These results are similar to those recorded in G. skottsbergii on both sides of the Drake Passage. Accordingly, I. cordata populations at both sides of the Drake Passage include two cryptic species. In this context, cryptic speciation plays an important role in the evolution of the Southern Ocean and accordingly, the systematic, biogeography and biodiversity of the region require major revisions.