Identification and growth of <i>Prorocentrum</i> cf. <i>cassubicum</i> (Dinoflagellata: Prorocentraceae) from Bahía de La Paz: first record for the Gulf of California

Abstract Prorocentrum includes ∼80 species inhabiting benthic and planktonic marine environments. Some species, such as Prorocentrum cassubicum and P . norrisianum , have similar morphology, which complicates their identification based solely on morphological characters. This study describes the morphometrics of two Prorocentrum strains (PNCETMAR-1 and PNCETMAR-2) isolated from the Ensenada de La Paz, Gulf of California. Sequences of the 28S and ITS regions of rDNA of both strains and the growth curve of strain PNCETMAR-1 were obtained. Strain PNCETMAR-1 was grown in modified GSe medium and f/2 medium at a salinity of 34, at 24 °C and 120–150 μmol m −2 s −1 in a 12 h light: 12 h dark cycle. There was no significant difference in growth between the culture media. In f/2 medium the maximum abundance was 74,312 ± 2,008 cells ml −1 , while in GSe medium it reached 69,766 ± 2,154 cells ml −1 . Morphometric and molecular analyses indicate that both strains belong to the same species. However, because the morphological and molecular information on P . cassubicum and P . norrisianum is contradictory, in this study they are reported as Prorocentrum cf. cassubicum , contributing to the first report of the occurrence and the growth of this species in the Gulf of California.