Complex Patterns of Diversification in the Gray Zone of Speciation: Model-Based Approaches Applied to Patagonian Liolaemid Lizards (Squamata: Liolaemus kingii clade)

In this study we detangled the evolutionary history of the Patagonian lizard clade Liolaemus kingii, coupling dense geographic sampling and novel computational analytical approaches. We analyzed nuclear and mitochondrial data (restriction site-associated DNA sequencing and cytochrome b) to hypothesize and evaluate species limits, phylogenetic relationships, and demographic histories. We complemented these analyses with posterior predictive simulations to assess the fit of the genomic data to the multispecies coalescent model. We also employed a novel approach to time-calibrate a phylogenetic network. Our results show several instances of mito-nuclear discordance and consistent support for a reticulated history, supporting the view that the complex evolutionary history of the kingii clade is characterized by extensive gene flow and rapid diversification events. We discuss our findings in the contexts of the gray zone of speciation, phylogeographic patterns in the Patagonian region, and taxonomic outcomes.

Automated summary

In this study, we used dense geographic sampling and novel computational analytical approaches to unravel the evolutionary history of the Patagonian lizard clade Liolaemus kingii. By analyzing nuclear and mitochondrial data, we were able to hypothesize and evaluate species limits, phylogenetic relationships, and demographic histories. Our results showed evidence of mito-nuclear discordance and supported a reticulated history with extensive gene flow and rapid diversification events in the kingii clade. We discussed the implications of our findings for speciation, phylogeography, and taxonomy in the Patagonian region.