no septa, no processes

Zonneveld, K.A.F. and Pospelova V. (2015). A determination key for modern dinoflagellate cysts. Palynology 39 (3), 387- 407.

Choose your cyst type

spherical to subspherical
spongy wall
some filaments larger
some filaments capitate
archeopyle split, selden loss of two plates
Bitectatodinium spongium +

spherical to subspherical
wall without enlarged filaments
archeopyle precingular by loss of two paraplates
Bitectatodinium tepikiense +

spherical to subspherical cysts
thick spongy wall
precigular archeopyle by loss of one plate
Tectatodinium pellitum +

spherical to cruciform
wall psilate, granulate to scabrate
archeopyle precingular by loss of one plate
Pyxidinopsis psilata +

subspherical to ovoid
wall has muri forming a reticulate pattern
sub-muri can be present
wall smooth to finely granulate
archeopyle precingular by loss of one ... +

spherical to subspherical cyst
smooth double wall
archeopyle precingular by loss of one plate
Ataxodinium choane +