Tectonic evolution of the Tethyan region created the Eurasian extratropical biodiversity hotspots: tracing Pireneitega spiders’ diversification history

Abstract

The withdrawal of the Tethys Sea and the formation of the Alpine‐Himalayan orogenic belt profoundly impacted the distribution and composition of terrestrial biota in Eurasia. However, studies that have explicitly addressed the potential links between the series of tectonic activities in the Tethyan region and the formation of extratropical biodiversity hotspots in the Alpine‐Himalayan belt are rare. Spiders in the genus Pireneitega (Agelenidae) are found throughout Eurasia and show high species richness in these hotspots. Thus, Pireneitega spiders may serve as a model group to shed light on how past tectonic events shaped Eurasian hotspots. To reconstruct the spatial and temporal evolution of Pireneitega spp., we conducted an integrative historical biogeographical analysis using thousands of novel DNA sequences and five novel transcriptome sequences from different species. Species distribution modelling based on complete geographical distribution information was used to assess the ecological preferences and the potential ecological interchangeability of Pireneitega species. Our study suggests that the rapid expansion of Pireneitega in Eurasia benefitted from regression of the Tethys Sea in the early Oligocene. Most Pireneitega species are distributed allopatrically, but in similar niches. The diversification of Pireneitega species relied on invading numerous new isolated habitats created by the uplift of Alpine‐Himalayan mountains during the Miocene (wet valley model). These results imply that the formation of Alpine‐Himalayan hotspots was driven by the series of tectonic events in the Tethyan region during the Oligocene–Miocene.