First record of Cochlodinium convolutum and C. helicoides (Gymnodiniales: Dinophyceae) in the Gulf of California

the naked marine dinoflagellates cochlodinium convolutum and c. helicoides are reported for the first time in the gulf of california. they occurred in seawater at 21-24.5°c. cochlodinium convolutum was found in both bottle and net samples; its abundance ranged from 400-2200 cells l_1. a total of 96 specimens of c. convolutum and 23 specimens of c. helicoides were examined from the net phytoplankton samples. a short description is given for each species, and photomicrographs provide information about the main morphological characteristics.