The presence of Arthronema africanum (Cyanophyceae/Cyanobacteria, Oscillatoriales) in Almería desert, SE Spain with implications on its biogeographical distribution

Arthronema africanum is a Pseudanabaenaceae (Cyanophyceae/Cyanobacteria) characterised by involution cells and trichome immobility. It grows in the soil covered by a salt crust in desert conditions. This species is described from localities of Libya and Kuwait included within the Saharo-Arabian Region and from an area of Spain within Mediterranean Region. This distribution can only be explained if these are primitive species from the end of the Triassic in the ancient continent of Pangea, which, after the continents drifted apart, were confined to xerothermic areas of the present day Holarctic Kingdom: Mediterranean and Saharo-Arabian Regions.