Systematic and biogeography of two sympatric octopuses from the remote Juan Fernández Archipelago, South Pacific Ocean.

Oceanic islands are hotspots of marine biodiversity, and biogeographic and evolutionary studies can provide important knowledge about the origin and diversification of the species that inhabit them. In the South Pacific, the Juan Fernández Archipelago (JFA) stands out for its high endemic biota, most of them endangered by human activities. Currently, two octopus species are recognized in JFA, but their taxonomic identity is not conclusive. In the present study, we performed morphometric and molecular analyses of both species inhabiting the JFA and contrast them with other species worldwide. Morphological, phylogenetic analysis, genetic diversity, and divergence times between species were estimated. Morphometric analysis did not show significant differences in body shape of males between/within Octopus species from JFA, only between females from different localities. However, phylogenetic and species delimitation analyses support the presence of two species in the JFA, namely Octopus mimus and Octopus vulgaris. In addition, both species show evidence of different divergence and colonization histories into the JFA during the Pleistocene. These findings do not only shed light on the identity, origin, and colonization time of the species, but also provide the basis to generate informed decisions on management and conservation. The recent colonization time and low genetic diversity observed in both species suggest that these populations are vulnerable to drastic changes, such as those caused by anthropic effects. [ABSTRACT FROM AUTHOR]