Evolutionary relationships of the Tehuelche scallop Aequipecten tehuelchus (Bivalvia: Pectinidae) from the south-western Atlantic Ocean

TROVANT, BERENICE; REAL, LUCIANO E.; PARMA, ANA M.; ORENSANZ, J.M.; BASSO, NÉSTOR G.

JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2019 p. 375 - 383

0025-3154

This study addresses aspects of the phylogenetic relationships of the commercial Tehuelche scallop, Aequipecten tehuelchus s.l.(Bivalvia: Pectinidae), from southern South America using molecular techniques. The Tehuelche scallop presents two differentputative subspecies, A. t. tehuelchus and A. t. madrynensis, and a potentially related sympatric species, Flexopecten felipponei.The Tehuelche scallop is a very important component of ecosystems and is the target of artisanal fisheries in the northernPatagonian gulfs of Argentina. Despite its importance, the systematic relationships of these taxa have not been fully addressed.The main goal of this study is to place the Tehuelche scallop within a partial phylogenetic framework of the family Pectinidae.Scallops were sampled at 10 localities distributed along the south-western Atlantic Ocean. Phylogenetic reconstructions werecarried out from two mitochondrial (12S rRNA and 16S rRNA) and two nuclear markers (28S rRNA and H3) using Bayesian,maximum likelihood and maximum parsimony analyses. Our phylogenetic analysis indicates that the two putative subspeciesof the Tehuelche scallop together with F. felipponei form a monophyletic clade, without differentiating at the specific level.Observed differences would be the result of phenotypic plasticity, probably caused by environmental factors. However,further analysis using genes with faster evolution rate are needed to corroborate it. Our phylogenetic analysis resolved toAequipecten as polyphyletic. The Tehuelche scallop has a basal position within the Argopecten group and we recommendthat it should be transferred to this genus. The relationship between the hypotheses about the origin of the Tehuelchescallop implicit in the literature and our results are discussed.