Morphology, Systematics, and Stratigraphic Significance of the Dinocyst Genus Dingodinium

Resumo

New material from the Upper Kimmeridgian and Volgian of the Gorodishche section (Ulyanovsk Region, Russia) allows a more accurate definition of the tabulation formula and archeopyle morphology of the dinocyst genus Dingodinium. The partiform pattern of the antapex and morphological features of the epicyst indicate that the genus Dingodinium should be attributed to the family Cladopyxiaceae of the suborder Cladopyxiineae. The genus Dingodinium as well as the species D. albertii, D. jurassicum, and D. tuberosum are revised, and a new species, D. nequeas, is described. In addition, the published data on Jurassic and Cretaceous species of the genus Dingodinium are analyzed and morphological criteria allowing their identification are recognized. Many species have a wide geographic distribution. Some species can be regarded as stratigraphically important for certain intervals of the Jurassic and Cretaceous.