CALCAREOUS DINOFLAGELLATE CYSTS IN MARINE-SEDIMENTS OF THE GULF OF NAPLES (MEDITERRANEAN-SEA)

Ten different calcareous cyst morphotypes were found in surface sedime nts of the Gulf of Naples. For four of them [Scrippsiella trochoidea ( Stein) Loeblich III, S. precaria Montresor and Zingone, S. lachrymosa Lewis and Pentapharsodinium tyrrhenicum (Balech) Montresor, Zingone an d Marine] the cyst-theca relationship was confirmed by germination exp eriments. These cysts constituted a large fraction (27-79%) of the ent ire dinoflagellate cyst assemblage of the Gulf of Naples and were part icularly abundant at stations close to the coast. Calcareous cyst popu lations were characterized by a species composition which differed fro m other coastal areas so far investigated. The relative abundance of c ysts until now only reported from fossil records (Calcicarpinum bivalv um Versteegh, which is the paleontologic name for the cyst of Pentapha rsodinium tyrrhenicum), or as rare in Recent sediments (e.g. Bicarinel lum tricarinelloides Versteegh, Follisdinellum splendidum Versteegh), appears to be a peculiar character of the cyst assemblage in the Gulf of Naples.