Ostreopsis lenticularis Y. Fukuyo (Dinophyceae, Gonyaulacales) from the South Atlantic Ocean: morphological and molecular characterization

Ostreopsis is a benthic dinoflagellate genus comprising eleven species including seven that are toxigenic. Ostreopsis lenticularis was first described from French Polynesia and is widely distributed in many insular locations from the Pacific Ocean. The current study presents morphological and molecular evidence of the presence of O. lenticularis at the Fernando de Noronha Archipelago, South Atlantic. Light microscopy and scanning electron microscopy of field cells showed morphological features in agreement with the description of O. lenticularis. Cells were broadly oval, 66.0–117.5 μm in dorso-ventral diameter, 50.0–92.5 μm in width, with thecal plates presenting two kinds of pores. Phylogenetic analyses based on LSU (D1-D3) and ITS sequences from field cells from Fernando de Noronha clustered with O. lenticularis sequences from elsewhere. The species was present in low to high abundances. The current study expands the distribution of O. lenticularis to Fernando de Noronha Archipelago in the South Atlantic Ocean. •First molecular evidence of Ostreopsis lenticularis occurrence in the Atlantic Ocean•O. lenticularis found in an oceanic island in Brazil at low to high abundances•New primers for ITS and LSU loci, specific to Ostreopsis lenticularis were developed.•Morphological and genetic characterization of O. lenticularis from Brazil provided•Brazilian O. lenticularis sequences similar to those from Tahiti (LSU) & Japan (ITS)