ORIGINAL ARTICLE Contrasting phylogeographical patterns for springtails reflect different evolutionary histories between the Antarctic Peninsula and continental Antarctica Angela McGaughran 1 *, Giulia Torricelli 1,2 , Antonio Carapelli 2 , Francesco Frati 2 , Mark I. Stevens 3 , Peter Convey 4 and Ian D. Hogg 5 INTRODUCTION Species genomes contain resolvable indications of past events. In particular, patterns of genetic variation within and among populations contain information about the origin and demog- raphy of a species. For example, measures of haplotype and nucleotide diversity can be used to identify population origins and colonization routes, because intraspecific diversity should 1 Allan Wilson Centre for Molecular Ecology and Evolution, Massey University, Palmerston North, New Zealand, 2 Department of Evolutionary Biology, University of Siena, Siena, Italy, 3 South Australian Museum, and School of Biological Sciences, Flinders University, Adelaide, Australia, 4 British Antarctic Survey, Natural Environment Research Council, High Cross, Cambridge, UK and 5 Centre for Biodiversity and Ecology Research, University of Waikato, Hamilton, New Zealand *Correspondence: Angela McGaughran, Allan Wilson Centre for Molecular Ecology and Evolution, Massey University, Private Bag 11-222, Palmerston North, New Zealand. E-mail: ang.mcgaughran@gmail.com ABSTRACT Aim We examined the genetic structure among populations and regions for the springtails Cryptopygus antarcticus antarcticus and Gomphiocephalus hodgsoni (Collembola) to identify potential historical refugia and subsequent colonization routes, and to examine population growth/expansion and relative ages of population divergence. Location Antarctic Peninsula for C. a. antarcticus; Antarctic continent (southern Victoria Land) for G. hodgsoni. Methods Samples were collected from 24 and 28 locations across the Antarctic Peninsula and southern Victoria Land regions for C. a. antarcticus and G. hodgsoni, respectively. We used population genetic, demographic and nested clade analyses based on mitochondrial DNA (cytochrome c oxidase subunit I and subunit II). Results Both species were found to have population structures compatible with the presence of historical glacial refugia on Pleistocene (2 Ma–present) time- scales, followed by post-glacial expansion generating contemporary geographically isolated populations. However, G. hodgsoni populations were characterized by a fragmented pattern with several ‘phylogroups’ (likely ancestral haplotypes present in high frequency) retaining strong ancestral linkages among present-day populations. Conversely, C. a. antarcticus had an excess of rare haplotypes with a much reduced volume of ancestral lineages, possibly indicating historical founder/bottleneck events and widespread expansion. Main conclusions We infer that these differences reflect distinct evolutionary histories in each locality despite the resident species having similar life-history characteristics. We suggest that this has predominantly been influenced by variation in the success of colonization events as a result of intrinsic historical glaciological differences between the Antarctic Peninsula and continental Antarctic environments. Keywords Antarctica, Collembola, Cryptopygus antarcticus antarcticus, demography, glaciation, Gomphiocephalus hodgsoni, population genetics, refugia, springtail. Journal of Biogeography (J. Biogeogr.) (2010) 37, 103–119 ª 2009 Blackwell Publishing Ltd www.blackwellpublishing.com/jbi 103 doi:10.1111/j.1365-2699.2009.02178.x