GYRODINIUM IMPUDICUM SP-NOV (DINOPHYCEAE), A NON TOXIC, CHAIN-FORMING, RED TIDE DINOFLAGELLATE

A new chain-forming dinoflagellate Gyrodinium inpudicum sp. nov., Gymn odiniaceae, is described from Valencia Harbour, Ria de Vigo (Spain) an d Fusaro Lagoon (Italy). The cingulum is a descending left spiral, dis placed between 1/3-1/4 of the total length of the cell and the sulcus is without torsion, two reasons why the new species is assigned to Gyr odinium. This red tide organism has been misidentified in several prev ious papers as Gymnodinium catenatum Graham or Polykrikos schwartzii B utschli. It differs from G. catenatum in cell shape and size of the ac robase. No paralytic shellfish poison (PSP) was found. G. impudicum ha s caused blooms in several areas but no associated harmful effects hav e been reported.