Article: A revision of the Triassic to lowest Jurassic dinoflagellate Rhaetogonyaulax

A re-evaluation of the dinoflagellate cyst genus Rhaetogonyaulax shows it to have a complex tabulation of 4'-?6', 5a-?6a, 1av, 7', 7c, 7'', 1p, 1pv, 3s, 3''. The archaeopyle is shown to be developed by loss of the epitract anterior to the precingular plate areas. In consequence of recognition of the high degree of intraspecific variability, all specimens examined are attributed to the single species R. rhaetica; the former species R. chaloneri is recognized as an extreme in the morphological range and reduced to varietal status.