Variable septa

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

smooth cavate septa
septa irregular
no intratabular ridges
scabrate cell wall
apical boss
Impagidinium variaseptum +

smooth cavate septa
septa irregular
intratabular ridges present
cyst wall finely granular
apical boss
Impagidinium caspienense +

solid septa
septa irregular
coarsly granulate to papillate wall
no apical boss
Caspidinium rugosum +

septa smooth,
septa higher at triple junction
small apical boss
smooth wall
tabulation reflected
Impagidinium aculaetum +