The Upper Jurassic-Lower Cretaceous dinoflagellate cyst Cannosphaeropsis thula Davey 1982 does not conform to the morphological parameters of the genus Cannosphaeropsis O. Wetzel 1933 emend. Duxbury 1980. The species also exhibits no indications of belonging to the Spiniferites complex of Evitt (1985). The species is transferred to Rotosphaeropsis Davey 1987 by virtue of its shape, archaeopyle type, processes and trabeculae and the specific diagnosis is emended in the light of this reassessment.
- Received May 1, 1988.
- Revision received March 1, 1989.
- © 1989 The Micropalaeontological Society