Aim: Comparative phylogeography seeks to unravel similarities in the population structure and evolutionary processes undergone by co-distributed taxa under the assumption that they will have experienced the same geoclimatic events. However, small differences in functional traits, particularly those related to dispersal abilities, may translate into incongruent evolutionary histories. Here, we used a sequence target multi-locus approach to infer and compare the phylogeographical patterns of three sympatric mygalomorph spiders in the Argentinean peripampasic orogenic arc.

Location: The mountainous systems of central and northern Argentina.

Taxon: Mygalomorphae spiders (Araneae)

Methods: We inferred the phylogeny of three species of mygalomorph spiders based on 16S+L1+nad1 and ITS sequences from one hundred and thirty-four individuals by using a Bayesian and Maximum likelihood approaches and we also estimated divergence dates. Also, nuclear networks were inferred. Based on our molecular phylogeny, we reconstructed ancestral areas using the the Bayesian Binary MCMC method.

Results: A deep genetic divergence and highly structured populations was obtained in the pycnothelid Acanthogonatus centralis, whereas the theraphosids Plesiopelma longisternale and Grammostola vachoni showed shallow divergences and poorly structured populations. Additionally, we uncovered potentially overlooked species diversity within G. vachoni, which warrants conducting a full taxonomic revision of Grammostola.

Main conclusions: We propose that differences in dispersion rates and time of colonization between the theraphosids and the pycnothelid led to divergent lineage history despite common environmental conditions. Our results further corroborate the key role played of the Plio-Pleistocene geoclimatic events in shaping the present-day diversity of mygalomorph spiders along the peripampasic orogenic arc.