Cryptic speciation in Southern Ocean Aequiyoldia eightsii (Jay, 1839): Mio-Pliocene trans-Drake Passage separation and diversification.

• Published in: Progress in Oceanography
• Main Authors: González-Wevar, Claudio A., Gérard, Karin, Rosenfeld, Sebastián, Saucède, Thomas, Poulin, Elie, Naretto, Javier, Díaz, Angie, Morley, Simon A., Brickle, Paul
• Other Authors: Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Instituto de Ecología y Biodiversidad (IEB), Laboratorio de Ecosistemas Marinos Antárticos y Subantárticos, Universidad de Magallanes, GAIA-Antártica, Universidad de Magallanes (UMAG), Biogéosciences UMR 6282 (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Departamento de Zoología, Universidad de Concepción = University of Concepción Chile (UdeC), British Antarctic Survey (BAS), Natural Environment Research Council (NERC), South Atlantic Environmental Research Institute UK, Joint Nature Conservation Committee, Study funded by the following projects and institutions: an Initiation Fondecyt Project (11140087), the Program FONDAP Project No. 15150003, Regular Fondecyt projects (1161358) and (1151336), projects P05-002 ICM and PFB 023 (Instituto de Ecología y Biodiversidad IEB), CD GAIA Antártica, Universidad de Magallanes, CONICYT PIA ACT172065.
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: Biogeography; Southern Ocean; Antarctic-Magellan Connection; Kerguelen Islands; Antarctic Peninsula; South America; Morphometry; Systematics; Phylogeny; [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics; Phylogenetics and taxonomy; Antarc*; Antarctic; Drake Passage; Tierra del Fuego
• Online Access: https://hal.science/hal-02182480; https://hal.science/hal-02182480/document; https://hal.science/hal-02182480/file/Gonza%CC%81lez-Wevar%20et%20al.pdf; https://doi.org/10.1016/j.pocean.2018.09.004

11 pages International audience The species of the genus Aequiyoldia Soot-Ryen, 1951, previously known as Yoldia, are common, soft-substratum, sareptid bivalves. In the Southern Ocean, Aequiyoldia eightsii (Jay, 1839) was originally described from the Antarctic Peninsula and has also been reported in southern South America. The species A. woodwardi (Hanley, 1960) was reported for the Falkland/Malvinas Islands and Tierra del Fuego, but this taxon has been recently synonymised within the broadly distributed A. eightsii. Aequiyoldia has received little attention across its distribution in the Southern Ocean, and although its taxonomy and systematics remain uncertain, all the species have been grouped under a single and broadly distributed unit: A. eightsii. Nevertheless, preliminary mtDNA comparisons demonstrated a marked genetic divergence (>7%) between A. eightsii populations from South America and Antarctic Peninsula. In order to further understand the diversity and biogeography of Aequiyoldia, we analyzed A. eightsii populations from different provinces of the Southern Ocean including South America (SA), the Falkland/Malvinas Islands (FI), the Antarctic Peninsula (AP), and Kerguelen Islands (KI). Individuals were characterized according to typical diagnostic morphological measurements and phylogenetic relationships were reconstructed based on mtDNA (cytochrome c oxidase subunit I). Patterns of genetic divergence of nucDNA intergenic transcribed spacers (ITS1, ITS2) were also estimated. The statistical analysis of external diagnostic characteristics revealed two morphotypes: (1) individuals with the morphology recorded for the nominal FI species, A. woodwardi, and (2) individuals from SA, AP, and KI, with the morphology recorded for A. eightsii. However, phylogenetic reconstructions based on mtDNA and nucDNA suggest the presence of at least five lineages within A. eightsii including: one lineage in Kerguelen Island, two lineages in the Antarctic Peninsula, one lineage in South America, and the last one ...