Taxonomic difficulties in red tide and paralytic shellfish poison studies: the "tamarensis complex" of Gonyaulax

The type illustrations of the dinoflagellate Gonyaulax tamarensis contain an apparent reversal of the epithecal plates. Furthermore a culture from the type locality has been found not to be toxigenic. These two features have led a recent author to doubt the appropriateness of the allocation of toxic populations in the North Atlantic to this species or a variety of it (var. excavata Braarud). The latter has been raised to the status of a distinct species but the wrong name has been applied to it (G. excavata) as, according to the rules of priority, it should be G. phoneus (Woloszynska & Conrad) nov. comb. A history of this confused situation is provided. The criteria by which other similar species are recognised are summarised. The necessity for further study on the specific distinction of these taxa is stressed. G. conjuncta has been so inadequately described or rejected. Variability in the plate pattern of a culture of G. tamarensis var. excavata from British Columbia is illustrated and its bearing on the taxonomy of the group discussed. The presence of this toxic variety on the west coast of N. America is a new record for the Pacific Ocean.