Islands in ice: isolated populations of Cryptopygus sverdrupi (Collembola) among nunataks in the Sør Rondane Mountains, Dronning Maud Land, Antarctica.

Molecular variation among Antarctic Collembola has been well appreciated over the last decade. The majority of studies have focussed on the Transantarctic Mountains and Antarctic Peninsula, and more recently Dronning Maud Land, which now accounts for all known continental species. Within most species, mean mitochondrial DNA (mtDNA) sequence divergence has not been more than around 2%, but in 2010 far greater levels of infraspecific sequence divergence (9.2–10.9%) were discovered in three species:Friesea grisea(10.2%),Gressittacantha terranova(10.4%) andCryptopygus antarcticus(9.2%). Here, we present the first phylogeographic study onCryptopygus sverdrupifrom Dronning Maud Land. We found that mtDNACOIand16Shaplotypes clustered into two lineages with a meanCOIsequence divergence of around 7.1%. The mixing of haplotypes between nearby nunataks separated by up to 15 km revealed support for ongoing (but rare) dispersal, although a single site, the most geographically isolated (by 40–58 km) was also the most genetically divergent. These levels of sequence divergence indicate persistence of biota throughout the Miocene and Pliocene isolated in glacial refugia. Expanding sampling ofC. sverdrupifrom additional ice-free refugia throughout Dronning Maud Land will be important to further our understanding of the evolutionary processes that have influenced the Antarctic continent, its landscape and biota. [ABSTRACT FROM PUBLISHER]