The radiation hypothesis championing rapid spread and colonization during the Gondwana fragmentation closely echoes the current distribution of the order. Presently, Anostraca are found on all seven continents. Most of the extant genera have restricted geographical distributions. Only three genera are widespread across the remnants of the former supercontinent Pangaea: "Artemia", "Branchinella" and "Branchinecta", while the remaining genera are found only throughout former Laurasia. This suggests that much of the potential habitat in this supercontinent, now occupied by Anostraca, to have been unoccupied by ecologically similar species, or to have been inhabited by species with less adaptive ability. Studies have found Anostraca capable of rapid colonization and speciation.