Morphological analysis of Mesozoic‐CenozoicCribroperidinium(Dinophyceae), and taxonomic implications.

Publisher Website
Google Scholar
Abstract
The morphologies of well preserved specimens assigned to six species of Cribroperidinium Neale and Sarjeant 1962 found in samples whose ages range from Hauterivian to Eocene were analyzed. Detailed observation of the paratabulation patterns in these specimens indicates on the epicyst: absence of a second preapical paraplate and dorsal contact of second and fourth apicals, and on the hypocyst: arcuate shape of posterior intercalary and posterior sulcal paraplates, six‐sided antapical paraplate with its right side longer than its left and its longitudinal axis inclined to the left of the cyst, and fourth postcingular paraplate offset to the left relative to the mid‐dorsal precingular one. A structure probably related to the ventral pore, reported in several species of modern gonyaulacoids, occurs in all the species studied. These characteristics serve as a basis for redefining Cribroperidinium, emphasizing the details of paratabulation topology as diagnostic criteria. Study of published descriptions of specimens assigned to this genus and to Millioudodinium Stover and Evitt 1978 indicates that the latter genus is a junior synonym of Cribroperidinium. Twelve new combinations are proposed and in addition 18 new combinations are provisionally proposed pending clarification of their paratabulation patterns.