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 DNA sequencing and cytochrome b) to hypothesize and evaluate species limits, phylogenetic relationships, and demographic histories. We also conducted posterior predictive simulations to assess the fit of the genomic data to the multispecies coalescent model. 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.