"Based on samples obtained in 2000-2002 from a 1-cm layer of surface sediment at two sites in Bahía Concepción in the Gulf of California, cyst-theca relationships were defined from cyst germination assays for Gonyaulax spinifera (= Spiniferites mirabilis), Protoceratium globosum, Preperidinium meunieri (= Dubridinium caperatum), Protoperidinium denticulatum (= Brigantedinium irregulare), and Protoperidinium cf. thorianum. All the taxa are illustrated with photomicrographs and descriptions of the resting and vegetative stages are given, including synonymy, size variation, distribution in Mexico, and global distribution, when known. As a result of cyst germination assays, the previously unknown cyst-theca relationship of P. globosum was described. We also confirmed the presence of the vegetative stage of P. denticulatum in the Gulf of California and heterospory in G. spinifera from Bahía Concepción. Cultures of G. spinifera and P. globosum were successfully established.""Mediante ensayos de germinación se logró definir la relación quiste-teca de Gonyaulax spinifera (= Spiniferites mirabilis), Protoceratium globosum, Preperidinium meunieri (= Dubridinium caperatum), Protoperidinium denticulatum (= Brigantedinium irregulare) y Protoperidinium cf. thorianum. Los quistes se aislaron a partir del primer centímetro de sedimento superficial de muestras colectadas durante el periodo 2000- 2002 en Bahía Concepción, Golfo de California. Los taxa identificados se ilustran con microfotografias, se describe la morfología de los estadios quístico y vegetativo, y también se incluye información sobre sinonimias, variación en talla y su distribución en México y en el mundo. Los ensayos de germinación permitieron describir por primera vez la relación uiste-teca de P. globosum, confirmar la presencia del estadio vegetativo de P. denticulatum en el Golfo de California y de la heterospori."