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Phylogeography recapitulates topography: very fine-scale local endemism of a saproxylic ‘giant’ springtail at Tallaganda in the Great Dividing Range of south–east Australia

Authors


Ryan Garrick, Fax: + 61 3 94792480; E-mail: r.garrick@latrobe.edu.au

Abstract

Comparative phylogeography can reveal processes and historical events that shape the biodiversity of species and communities. As part of a comparative research program, the phylogeography of a new, endemic Australian genus and species of log-dependent (saproxylic) collembola was investigated using mitochondrial sequences, allozymes and anonymous single-copy nuclear markers. We found the genetic structure of the species corresponds with five a priori microbiogeographical regions, with population subdivision at various depths owing to palaeoclimatic influences. Closely related mtDNA haplotypes are codistributed within a single region or occur in adjacent regions, nuclear allele frequencies are more similar among more proximate populations, and interpopulation migration is rare. Based on mtDNA divergence, a late Miocene–late Pliocene coalescence is likely. The present-day distribution of genetic diversity seems to have been impacted by three major climatic events: Pliocene cooling and drying (2.5–7 million years before present, Mybp), early Pleistocene wet-dry oscillations (c. 1.2 Mybp) and the more recent glacial-interglacial cycles that have characterized the latter part of the Quaternary (< 0.4 Mybp).

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