The disjunct distribution of the harvestman Discocyrtus dilatatus (Opiliones, Gonyleptidae) is used as a case study to test the hypothesis of a trans-Chaco Pleistocene paleobridge during range expansion stages. This would have temporarily connected humid regions ('Mesopotamia' in northeastern Argentina, and the 'Yungas' in the northwest, NWA) in the subtropical and temperate South American lowl...