Exochosphaeridium alisitosense n. sp.; a new gonyaulacoid dinoflagellate from the Albian of Baja California, Mexico

Abstract

A new species of skolochorate dinoflagellate cyst, Exochosphaeridium alisitosense, from upper Albian strata in Baja California, Mexico is described. The genus Exochosphaeridium is emended to include fossil dinoflagellate cysts with nontabular to intratabular processes, occasionally modified in the antapical area and with a short apical horn, and assigned to the subfamily Cribroperidinioideae. E. alisitosense, has intratabular processes and a reticulate antapical area that together with the adjacent paraplates, delineates a symmetrical sexiform arrangement with dextral torsion. This species also has an S-type ventral organization with an A/ai paratabulation pattern.