A MULTILOCUS PERSPECTIVE ON REFUGIAL ISOLATION AND DIVERGENCE IN RAINFOREST SKINKS ( CARLIA )

Abstract

To explore the evolutionary consequences of climate-induced fluctuations in distribution of rainforest habitat we contrasted demographic histories of divergence among three lineages of Australian rainforest endemic skinks. The red-throated rainbow skink, Carlia rubrigularis,consistsof morphologicallyindistinguishable northern and southern mitochondrial DNA (mtDNA) lineages that are partially reproductively isolated at their parapatric boundary. The third lineage (C. rhomboidalis)inhabits rainforestsjusttothesouthof C. rubrigularis,hasblue, rather than red-throated males, and for mtDNA is more closely related to southern C. rubrigularis than is northern C. rubrigularis.Multigene coalescent analyses supported more recent divergence between morphologically distinct lineages than between mor- phologically conservative lineages. There was effectively no migration and therefore stronger isolation between south- ern C. rubrigularis and C. rhomboidalis,and lowunidirectional migrationbetweenmorphologically conservative lineages of C. rubrigularis.Wefoundlittleornoevidence forstrong differences in effective population size, and hence different contributions of genetic drift in the demographic history of the three lineages. Overall the results suggest contrasting responses to long-term fluctuations in rainforest habitats, leading to varying opportunities for speciation. Key