Abstract

The genus Prorocentrum comprises several benthic dinoflagellate species known to produce diarrhetic shellfish poisoning (DSP) toxins. However, information on their distribution and toxic potential remains limited across large areas of the Polynesian region. In this study, a clonal strain D008-7, isolated from intertidal tide pools in Rapa Nui (Easter Island), was analyzed using an integrative approach combining morphological observations, molecular phylogenetic analyses, and toxicological characterization by LC-MS/MS. Morphological and molecular results conclusively identified the strain as P. caipirignum. Toxin analysis revealed the production of okadaic acid (OA), predominantly in esterified form, while dinophysistoxins DTX1 and DTX2 were not detected. These findings extend the known geographic range of P. caipirignum to the easternmost boundary of the Polynesian Triangle and offer novel insights into its toxin profile in a highly isolated oceanic island environment.