Same place, different stories: Disparate evolutionary trends of mygalomorph spiders from the Peripampasic orogenic arc

Abstract

Aim Comparative phylogeography aims 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 Acanthogonatus centralis, Grammostola vachoni and Plesiopelma longisternale (Araneae: Mygalomorphae). Methods We inferred mitochondrial gene trees (16S + L1 + nad1) and nuclear (ITS2) networks of three species of mygalomorph spiders from 159 individuals using Bayesian and Maximum likelihood approaches, and estimated divergence times in a Bayesian framework. Based on our time‐stamped gene trees, we reconstructed ancestral areas using the Bayesian Binary MCMC method. Results Deeply divergent and highly geographically structured populations, isolated since the Late Miocene to mid Pliocene, were obtained in the pycnothelid Acanthogonatus centralis. Conversely, the theraphosids Plesiopelma longisternale and Grammostola vachoni showed slightly divergent and poorly geographically structured populations, tracing back to the Late Pliocene to Early Pleistocene. Main conclusions We propose that differences in dispersion rates and time of colonization between the theraphosids and the pycnothelid species led to divergent lineage history despite common environmental conditions. We corroborate the key role played by the Plio‐Pleistocene geoclimatic events in shaping the present‐day diversity of mygalomorph spiders along the Peripampasic orogenic arc. Additionally, we uncovered potentially overlooked species diversity within G. vachoni.

Geography, climate and shifts in host plants distribution explain the genomic variation in the cactus moth

“…Subsequently, during the Quaternary, major climatic shifts took place in the area, leading to the isolation of the Chacoan xeric woodlands from the typical grasslands of the Pampean region. Such climatic changes were promoted by the topographic reconfiguration of Andean and sub-Andean Piedmont and the uplift of the eastern orographic systems (known as the Sierras Pampeanas) associated with the Peripampasic orogenic arc (Ortiz-Jaureguizar and Cladera, 2006;Speranza et al, 2007;Calatayud-Mascarell et al, 2022). These events produced a rain-shadow effect that resulted in the extreme xeric conditions that prevailed in this area.…”