A review of the Jurassic dinocyst genera Ctenidodinium Deflandre 1938 and Dichadogonyaulax Sarjeant 1966
Woollam, R.; Woollam, R.; Institute of Geological Sciences; BP Research Centre
Журнал:
Palynology
Дата:
1983
Аннотация:
AbstractThe historical development of the study of the Jurassic dinocyst (dinoflagellate cyst) genera Ctenidodinium Deflandre 1938 and Dichadogonyaulax Sarjeant 1966 is outlined, and various aspects of their paratabulation and archaeopyle structure are discussed. The gonyaulacoid paratabulation is topologically constant, with the exception of the insertion of two small anterior intercalary paraplates and/or several pre‐apical paraplates in some species. This is true despite geometric changes to individual paraplates, particularly on the ventral area of the hypocyst and on the hypo‐cyst in general. The mode of excystment consists of a principal archaeopyle suture which runs along a line immediately anterior to the paracingulum, the operculum (the complete epicyst) remaining attached at the parasulcus, with no accessory archaeopyle sutures occurring. The generic concepts of Ctenidodinium and Dichadogonyaulax are emended, and two new genera, Bradleyella gen. nov. and Korystocysta gen. nov. are proposed. Each genus is characterized by their overall cyst morphology, including the presence or absence of an apical horn, paracingular crest symmetry or asymmetry and overall crest development, in conjunction with paratabulation (geometric) detail.
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