Abstract
Marine and freshwater gastrotrich fauna from the Island of Montecristo (Tuscan Archipelago) is reported. Thirteen macrodasyid and six chaetonotid species were found in marine sandy sediments from four collecting sites. The new species Lepidodasys unicarenatus and Tetranchyroderma insulare ate described. Nine chaetonotid species were collected from the inland waters of the island, and the new species Chaetonotus (Schizochaetonotus) oplites is described. A comparison between the gastrotrich fauna of Montecristo and that of other islands in the archipelago and of the Tuscan littoral is drawn.