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First evidence of Ostreopsis cf. ovata in the eastern tropical Pacific Ocean, Ecuadorian coast

Abstract:

Ostreopsis cf. ovata has become one of the most studied toxic dinoflagellates in the last decade due to the production of palytoxin-like analogues by some of the strains. Nonetheless, its taxonomy is still unresolved, as the morphological features are not well defined. Currently, three genetic clades of O. cf. ovata occurring in overlapping geographical areas, and several different toxicity patterns have been described. In this investigation, 13 isolates from the coast of Ecuador in the eastern Pacific Ocean, including a geographical area from which no information existed, were analyzed for Ostreopsis genotypes and toxicity of the O. cf. ovata complex. By analyzing the ITS and 5.8S rDNA, the isolates were found to be identical and to cluster in the Atlantic/Indian/Pacific clade, and they were not toxic according to hemolytic assays. The absence of palytoxin-like compounds was confirmed by liquid chromatography-mass spectrometry. The results are discussed in light of the current situation of O. cf. ovata strains, whose study has been traditionally restricted to some areas such as the Mediterranean Sea and the western Pacific Ocean. We also review the information regarding toxicity and molecular biology of O. cf. ovata strains in order to contribute to current understanding of the species complex.