Mesozoic operculate pollen and their morphology

Abstract

Operculate pollen referable to the subturma Operculati Venkatachala and Goczan, are common in the Mesozoic sediments. The genera included under this group are Classopollis (Pflug) Pocock and Jansonius, 1961; Gliscopollis gen. nov. [=Corollina MALJAWKINA, 1949 and Circulina (Maljawkina) KLAUS, 1960] and Granuloperculatipollis Venkatachala and Goczan, 1963. All the three genera are monoporate often with a distinct distal operculum and possessing a faintly discernible to distinct proximal trilete mark. Two main trends of specialization could be visualized in the group: (i) disappearance of the trilete mark and (ii) prominence and delimitation of the ring tenuitas bordering the operculum. Pollen belonging to this group are known to occur among the conifers referable to Cheirolepidaceae.