Mite dispersal among the Southern Ocean Islands and Antarctica before the last glacial maximum

• Published in: Proceedings of the Royal Society B: Biological Sciences
• Main Authors: Mortimer, E., Jansen van Vuuren, B., Lee, J. E., Marshall, D. J., Convey, P., Chown, S. L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2010
• Subjects: Antarc*; Antarctic; Antarctica; Southern Ocean; Mite
• Online Access: http://dx.doi.org/10.1098/rspb.2010.1779; https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2010.1779; https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2010.1779

It has long been maintained that the majority of terrestrial Antarctic species are relatively recent, post last glacial maximum, arrivals with perhaps a few microbial or protozoan taxa being substantially older. Recent studies have questioned this ‘recolonization hypothesis’, though the range of taxa examined has been limited. Here, we present the first large-scale study for mites, one of two dominant terrestrial arthropod groups in the region. Specifically, we provide a broad-scale molecular phylogeny of a biologically significant group of ameronothroid mites from across the maritime and sub-Antarctic regions. Applying different dating approaches, we show that divergences among the ameronothroid mite genera Podacarus , Alaskozetes and Halozetes significantly predate the Pleistocene and provide evidence of independent dispersals across the Antarctic Polar Front. Our data add to a growing body of evidence demonstrating that many taxa have survived glaciation of the Antarctic continent and the sub-Antarctic islands. Moreover, they also provide evidence of a relatively uncommon trend of dispersals from islands to continental mainlands. Within the ameronothroid mites, two distinct clades with specific habitat preferences (marine intertidal versus terrestrial/supralittoral) exist, supporting a model of within-habitat speciation rather than colonization from marine refugia to terrestrial habitats. The present results provide additional impetus for a search for terrestrial refugia in an area previously thought to have lacked ice-free ground during glacial maxima.