Origin and Age of the Marine Stygofauna of Lanzarote, Canary Islands

Five species of troglobitic crustaceans, previously known only from the Jameos del Agua marine lava tube in Lanzarote, Canary Islands, have been collected from wells in other, geologically older areas of the island. Most, and possibly all, of the endemic species inhabiting the Jameos del Agua probably entered the cave from adjacent crevicular groundwater habitats. The endemic hypogean fauna of Lanzarote can be divided into 2 groups: (1) relict species with affinities to the cave fauna of other oceanic, primarily Western Atlantic, islands and (2) species with close relatives from the deep sea. The origin of the first group can be correlated to Mesozoic plate tectonics. The species of the second group are probably derived from widely spread deep sea ancestors and may have colo­ nized the crevicular system of Lanzarote at different times.