Evidence from HPLC pigment analyses supports the assignment of several dinoflagellate species to a new genus. The carotenoid gyroxanthin-diester has previously been reported in several species of dinoflagellates including Gymnodinium breve Davis, G. galatheanum Braarud and Gyrodinium aureolum Hulbert. In the study reported here, four other dinoflagellate species have been found to contain gyroxanthin-diester as well as chlorophyll c1/c2, chlorophyll c3 and diadinoxanthin. The fucoxanthin and 19\'-acylofucoxanthin complements show species-specific differences, varying widely from near equal quantities of each to exclusively 19\'-acylofucoxanthin. Two isolates of Gymnodinium mikimotoi, one from New Zealand and one from Japan, had nearly indistinguishable pigment complements. This group of dinoflagellates identified as being substantially dissimilar from other genera to warrant a new genus do not contain peridinin. These results from the pigment analyses will be presented in conjunction with other presentations which will discuss the molecular, morphological, ultrastructural, biochemical and toxin data that support the suggestion of a new genus.