A multilocus perspective on refugial isolation and divergence in rainforest skinks (Carlia)

Area of Science:

• Evolutionary biology
• Herpetology
• Climate change impacts

Background:

• Australian rainforest skinks provide models for studying climate-driven evolutionary changes.
• Habitat fragmentation due to climate change can lead to population divergence and speciation.
• Understanding demographic histories is crucial for inferring evolutionary processes.

Purpose of the Study:

• To investigate the evolutionary consequences of climate-induced rainforest habitat shifts.
• To contrast the demographic histories and divergence patterns of three Australian rainforest skink lineages.
• To assess the role of migration, reproductive isolation, and genetic drift in lineage divergence.

Main Methods:

• Comparative analysis of demographic histories using multigene coalescent analyses.
• Examination of mitochondrial DNA (mtDNA) to infer lineage relationships.
• Assessment of migration rates and reproductive isolation between lineages.

Main Results:

• More recent divergence was observed between morphologically distinct skink lineages compared to morphologically similar ones.
• Effectively no migration and stronger isolation were found between southern Carlia rubrigularis and Carlia rhomboidalis.
• Low unidirectional migration occurred between the northern and southern Carlia rubrigularis lineages.

Conclusions:

• Long-term rainforest habitat fluctuations result in contrasting evolutionary responses among skink lineages.
• Varying degrees of isolation and migration influence speciation opportunities.
• Genetic drift does not appear to be a primary driver differentiating the demographic histories of these lineages.