Did post-glacial sea-level changes initiate the evolutionary divergence of a Tasmanian endemic raptor from its mainland relative?

Populations on continental islands are often distinguishable from mainland conspecifics with respect to body size, appearance, behaviour, or life history, and this is often congruent with genetic patterns. It is commonly assumed that such differences developed following the complete isolation of populations by sea level rise following the Last Glacial Maximum (LGM). However, population divergence may pre-date the LGM, or marine dispersal and colonisation of islands may have occurred more recently; in both cases, populations may have also diverged despite on-going gene flow. Here we test these alternative hypotheses for the divergence between wedge-tailed eagles from mainland Australia (Aquila audax audax) and the threatened Tasmanian subspecies (A. a. fleayi), based on variation at 20 microsatellite loci and mtDNA. Coalescent analyses indicate that population divergence appreciably post-dates the severance of terrestrial habitat continuity, and occurred without any subsequent gene flow....