New records of Asterodinium Sournia (Brachidiniales, Dinophyceae)

New records of species of the rare planktonic dinoflagellate genus Asterodinium Sournia are reported. From the Mediterranean Sea and NE Atlantic Ocean: (1) three specimens of Asterodinium sp. sensu Sournia from the Gulf of Cadiz and Strait of Gibraltar (NE Atlantic Ocean), (2) one specimen of Asterodinium sp.1 from the Strait of Gibraltar, (3) three specimens of Asterodinium cf. libanum Abboud-Abi Saab from the Bay of Villefranche-sur-Mer (Ligurian Sea, NW Mediterranean Sea), (4) three specimens of Asterodinium gracile from the Tyrrhenian Sea and Strait of Sicily (Mediterranean Sea). Most taxa were recorded from 70 to 100 m depth, with exceptions in the Strait of Gibraltar and the Corsica Channel. From a longitudinal transect (138degreesE) in the Philippine Sea (NW Pacific Ocean) are reported: (5) four specimens of Asterodinium gracile, (6) Asterodinium cf. gracile, (7) one specimen of Asterodinium sp.1 and (8) Asterodinium sp.2. These records were collected between 50 to 175 m depths. Asterodinium gracile shows high morphological variation. The ecology of the genus is reviewed and discussed.