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The thermohaline expressway: the Southern Ocean as a centre of origin for deep‐sea octopuses |
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| Authors: | Jan M Strugnell Alex D Rogers Paulo A Prodöhl Martin A Collins A Louise Allcock |
| Institution: | 1. Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK;2. School of Biological Sciences, Queen’s University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK;3. British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Rd, Cambridge CB3 0ET, UK;4. Institute of Zoology, Zoological Society of London, Regent’s Park, London NW1 4RY, UK;5. Martin Ryan Marine Science Institute, National University of Ireland, Galway, University Road, Galway, Ireland |
| Abstract: | Understanding how environmental forcing has generated and maintained large‐scale patterns of biodiversity is a key goal of evolutionary research and critical to predicting the impacts of global climate change. We suggest that the initiation of the global thermohaline circulation provided a mechanism for the radiation of Southern Ocean fauna into the deep sea. We test this hypothesis using a relaxed phylogenetic approach to coestimate phylogeny and divergence times for a lineage of octopuses with Antarctic and deep‐sea representatives. We show that the deep‐sea lineage had their evolutionary origins in Antarctica, and estimate that this lineage diverged around 33 million years ago (Ma) and subsequently radiated at 15 Ma. Both of these dates are critical in development of the thermohaline circulation and we suggest that this has acted as an evolutionary driver enabling the Southern Ocean to become a centre of origin for deep‐sea fauna. This is the first unequivocal molecular evidence that deep‐sea fauna from other ocean basins originated from Southern Ocean taxa and this is the first evidence to be dated. © The Willi Hennig Society 2008. |
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