Aim The mid‐Miocene closure of the Tethys (Terminal Tethyan Event, TTE) induced by the collision of the African–Arabian plate with the Eurasian plate is considered to be a major driver of tropical marine biodiversity. We used intertidal talitrids of Talorchestia sensu lato to test the hypothesis that the TTE can best explain the current disjunct distribution of this genus along Mediterranean‐East Atlantic and Indo‐West Pacific coastlines. Location Mediterranean‐East Atlantic and Indo‐West Pacific. Methods We sequenced four nuclear and two mitochondrial loci for 87 samples across the Mediterranean‐East Atlantic to Indo‐Pacific areas. We examined phylogenetic relationships, estimated divergence times and reconstructed ancestral geographical distributions of Talorchestia sensu lato within a wide geographical context. Results The phylogenetic analyses revealed that Talorchestia sensu lato is monophyletic. Divergence time estimation and ancestral range reconstruction show that the genus originated from the Tethys during the Miocene and split into Mediterranean‐East Atlantic and Indo‐West Pacific lineages c. 15 Ma. The Mediterranean‐East Atlantic lineage further diverged into west and east Mediterranean clades, and the Indo‐West Pacific lineage contains Indian Ocean and west Pacific clades. Main conclusions The evolutionary history of Talorchestia sensu lato corresponds well with the geological history of Tethyan closure, suggesting that the Tethyan closure drove the vicariant diversification of Talorchestia sensu lato into Mediterranean‐East Atlantic and Indo‐West Pacific lineages. This indicates that the intertidal environment may be the last to be separated by the TTE, and the diversification pattern of intertidal crustaceans can best reflect the vicariance effect of Tethyan closure. Deep divergences within clades were related to geological isolation in the Mediterranean‐East Atlantic region and across the Indo‐Pacific boundary.

Climate changes have substantial impacts on the geographic distribution of montane lakes and evolutionary dynamics of cold‐adapted species. Past climate cooling is hypothesized to have promoted the dispersal of cold‐adapted species via montane lakes, while future climate warming is thought to constrain their distributions. We test this hypothesis by using phylogeographic analysis and niche modeling of the Holarctic crustacean Gammarus lacustris with global sampling comprised of 567 sequenced individuals and 3180 occurrence records. We found that the species arose in Tian Shan in Central Asia and dispersed into montane lakes along the Alps, Himalayas, Tibet, East Asia, and the North American Rocky Mountain ranges, with accelerated diversification rates outside Tian Shan. Climatically suitable regions for geographic lineages of G. lacustris were larger during cooling periods (LGM), but smaller during warming periods (Mid‐Holocene). In the future (2070) scenario, potential distributions in the Himalayas, North Tibet, South Tibet and North America are predicted to expand, whereas ranges in East Asia, Europe and Tian Shan will decline. Our results suggest that Mid‐Miocene‐to‐Pleistocene continuous cooling promoted multiple independent dispersal events out of Tian Shan due to increased availability of montane lakes via “budding” of lineages. Montane lakes are conduits through which cold‐adapted amphipods globally dispersed, dominating circumboreal lakes. However, future climate warming is likely to force organisms to shift upward in altitude and northward in latitude, leading to a future change in local populations. These findings highlight the importance of conservation of montane lakes, especially in the context of climate change.