Species of Minidiscus (Bacillariophyceae) in the Mexican Pacific Ocean

Minidiscus species are the smallest centric diatoms of the marine phytoplankton (with diameters ranging from 1.9 to 7.5 mum), and they may be easily overlooked in routine analyses. Three species of the genus occurred in samples collected in the Mexican Pacific Ocean: Minidiscus trioculatus, M. comicus and M. chilensis. The identification of these species represents the first documented records for the Mexican Pacific: Minidiscus trioculatus and M. chilensis off the west coast of Baja California, and M, comicus in the Gulf of Tehuantepec. Minidiscus trioculatus is considered a cosmopolitan species, M. comicus has a wide distribution in subtropical-temperate waters, and M. chilensis may be mainly regarded as a temperate to cold-water form. (C) 2001 Adac/Editions scientifiques et medicales Elsevier SAS.