Abstract

Research carried out on the Upper Jurassic dinoflagellate cyst assemblages of the Sub-Tethyan marine realm, show that populations of the dinoflagellate cysts Subtilisphaera? inaffecta and S.? paeminosa are predominant in shallow water marginal marine or brackish environments. The distribution of groups of dinoflagellate cysts, micrhystridid acritarchs and variations of terrestrial inputs represented by phytoclasts are presumed parameters of the salinity balance during such Late Jurassic depositional environments. In this context, the shagreenate to faintly granulate S.? inaffecta appears to be an opportunistic taxon with an ability to prosper in brackish environments. In contrast, the coarsely granulate to pustulate paeminosa form is seemingly less eurytopic and flourishes with success in shallow, marginal marine, environments. SEM studies reveals that the two morphotypes possess transapical archaeopyle sutures on what is usually considered the antapex. Following these observations the cysts are interpreted in a reverse sense. Consequently, the attribution to the genus Subtilisphaera becomes inappropriate. The two morphotypes, interpreted as variants of a single species, are attributed to the genus CorculodiniumBatten & Lister, 1988 for which a new emendation is proposed. The specific epithet inaffecta is considered legal over paeminosa.

You do not currently have access to this article.