Following the Antarctic Circumpolar Current: patterns and processes in the biogeography of the limpetNacella(Mollusca: Patellogastropoda) across the Southern Ocean

Abstract

AbstractAimWe use an integrative biogeographical approach to further understand the evolution of an important Southern Ocean marine benthic element, the limpet genusNacella(Mollusca: Patellogastropoda).LocationSouthern Ocean.MethodsWe used multi‐locus time‐calibrated phylogeny ofNacellaat the scale of the whole Southern Ocean to elucidate the underlying processes involved in the origin and diversification of the genus.ResultsDivergence‐time estimates suggest that soon after its origin during the mid‐Miocene (c. 12.5 Ma),Nacellaseparated into two main lineages currently distributed in (1) South America and (2) Antarctica and the sub‐Antarctic islands. We identified two pulses of diversification, during the late Miocene (8 to 5.5 Ma) and the Pleistocene (< 1 Ma).Main conclusionsMajor periods of climatic and oceanographical change strongly affected the biogeography ofNacellaand demonstrate both the long‐ and short‐term influence of the Antarctic Circumpolar Current across the Southern Ocean. Our analyses support the validity of all currently recognizedNacellaspecies and reveal a new South‐American lineage. This work constitutes the most detailed molecular‐based study of an ecologically important, near‐shore invertebrate Southern Ocean group and in so doing contributes to the improved understanding of the underlying patterns and processes in the origin and diversification of marine benthic fauna across this globally important region.