Durotrigia daveyi gen. et sp. nov. is described from the Inferior Oolite (Early Bajocian) of Dorset, England. It is the earliest distinctly tabulated gonyaulacacean dinocyst with a precingular archaeopyle. The archaeopyle is apparently variable, involving the loss of between 1 and 5 precingular plates. This variability poses some interesting taxonomic problems, particularly the implications to the value of the archaeopyle type as a high-level classification criterion. Some possible causes of archaeopyle variability are discussed.
- Received April 1, 1987.
- Revision received August 1, 1987.
- © 1987 The Micropalaeontological Society