Naresh C. Mehrotra

Late Cretaceous to early tertiary Dinoflagellate cysts from Narasapur Well-1, Godavari-Krishna basin, South India

Abstract Dinoflagellate cyst assemblages are described fromsome of the richest horizons in the Narasapur Well-1, Godavari-Krishna basin, Andhra-Pradesh, India. Twenty-five taxa belonging to nineteen genera are recorded. The majority exhibit close morphological similarity with species described earlier from Europe, North America and Australia. One new genus, Godavariella, and three new species, Godavariella venkatachalae, Fibrocysta variabilis and Cyclonephelium indicum, are proposed; several more new forms are described but, since meagrely represented, are not named. The dinoflagellate assemblages, along with spore and pollen studies carried out earlier by Venkatachala & Sharma (1984) , suggest a Late Cretaceous (Maastrichtian) to Early Tertiary (Palaeocene) age for these sediments.

The dinoflagellate cyst genus Polygonifera; emendation and taxonomic stabilization

The taxonomic identity of the dinoflagellate cyst genus Polygonifera Habib, 1972 is confirmed, through the recognition of additional morphological characters during the study of specimens from Early-Middle Cretaceous sediments of India. A revised definition of this genus is presented. Leberidocysta Stover & Evitt, 1978 is considered a subjective junior synonym of Polygonifera and its type species Leberidocysta (ex: Hexagonifera) chlamydata (Cookson & Eisenack) is transferred to Polygonifera. The other species placed in Leberidocysta are provisionally reattributed to other genera, becoming Craspedodinium (ex: Hexagonifera) defloccata (Davey), Craspedodinium (ex: Palaeostomocystis) pergamentacea (Burger), Hexagonifera laticaudata Vozzhennikova and Hexagonifera scabrata Jain & Taugourdeau-Lantz. A new species, Polygonifera eisenackii, is described. Morphological differences between the camocavate genera Polygonifera and Dingodinium are clarified.

Early to Middle Cretaceous dinoflagellate cysts from the Periyavadavadi Shallow well-1, Cauvery basin, India

Abstract Assemblages of Lower-Middle Cretaceous dinoflagellate cysts are described from the sediments of India for the first time. They were obtained from subsurface sediments of Periyavadavadi Shallow well-1, Cauvery basin. Twenty-seven morphotypes, belonging to at least eighteen genera, occur in these sediments, the majority showing close morphological comparability with taxa described earlier from Australia and Europe. One new subspecies, Cyclonephelium distinctum subsp. laevigatum, is proposed; other new taxa are described but, since meagrely represented, are not named. The generic diagnosis of Aprobolocysta Duxbury , 1977 emend. Duxbury , 1980 , is again revised. The assemblages, along with evidence from spores and pollen published earlier by Venkatachala & Sharma (1974) , indicate a Valanginian to Aptian age for the sediments studied.

Neoproterozoic age based on microbiotas from the Raipur Group of Baradwar sub-basin, Chhattisgarh

An assemblage of structurally preserved organic-walled microfossils (OWMs) from the macerated residue of black carbonaceous shale belonging to Saradih Formation, the youngest carbonate horizon of the Raipur Group, Chhattisgarh Supergroup exposed at on the right bank of Mahanadi River, NE of Sarangarh township in Raigarh district, Chhattisgarh is being reported for the first time. The assemblage is comprised of 19 taxa of 13 genera belong to eukaryotes and prokaryotes viz. Leiosphaeridia, Stictosphaeridium, Dictyotidium, Synsphaeridium, Symplassosphaeridium, Satka, Trachysphaeridium, Goniosphaeridium, Trachyhystrichosphaera, Vandalosphaeridium, Siphonophycus, Oscillatoriopsis and Polythrichoides. The comprehensive account of recovered microbiotic assemblage can be correlated with globally known Neoproterozoic (early Cryogenian) assemblages, deposited in tidal complexes of shallow sea.