A new record of Azadinium spinosum (Dinoflagellata) from the tropical Mexican Pacific

The species Azadinium spinosum, a small thecate dinoflagellate, originally and recently described from the North Sea, was found for the first time in the tropical Pacific coast of Mexico. Description by light and scanning electron microscopy and abundance data are here provided. The morphology of the species agrees with the original description, including size, shape, presence of posterior spine and tabulation details. Less than 300 cells L^-1 were found in one station in the Pacific coast of Mexico. This species has been recognized as a producer of azaspiracid toxins (AZAs) in the North Sea, although no toxin analysis has been made as yet in Mexican waters.