Conclusions
Stasimopus is an ancient group of spiders in the Karoo region. The genus has radiated from the late Eocene and through the Miocene resulting in 15 extant species in the region. The similarities in biogeographic histories between the Karoo and arid region of western Australia have seemly affected the mygalomorph fauna in similar ways. More mygalomorph genera are needed to determine if this holds true. The Tankwa Karoo is possibly of importance as a Pleistocene glacial cycle refugia for the species S. leipoldti . The area should receive additional sampling to determine if it is a refugia for other taxa. Many of the species are short range endemics, making them of higher conservation concern. This is important to note as the Karoo is undergoing further desertification due to factors such as climate change. The genus has thrived under arid conditions, but this rapid desertification may push the various species to their adaptational limits.