De “kosmopolitische” verspreiding van Pisidium casertanum

Title: The so-called kosmopolitan distribution of Pisidium casertanum (Poli). The author considers this species to be autochtonous in the northern temperate zones. In tropical climates it does not occur in lowlands and secundary mountain-chains. It is, however, present in several high mountains in South America, Africa and Asia. A rather recent (Holocene) dispersal by birds is probable. Up till now, no fossil records of casertanum are known from the Southern Hemisphere. In southern localities it mostly lives associated with an endemic species of the genus.