Lapideacassis mariae Black, 1971b
Pervilithus Crux, 1981
Large cone shape nannolith having a narrow wall with proximal tier, collar, two distal tiers and a cone. Elongated longitudinal laths make the wall, and ledges mark the junction of different tiers. The apical spines may or may not be present. Lapideacassis is distinguished from Scampanella Forchheimer & Stradner (1973) by having only two distal tiers. Until now, species of Lapideacassis is distinguished based on the number and arrangement of the spine present. However, the presence or absence of the spine and their number are strongly influenced by the adverse preservational conditions; therefore, the spine number is not ideal for taxonomic classification.
Black, M., 1971b. Problematical Microfossils from the Gault Clay. Geological Magazine 108(4), 325-327.
Crux, J. A., 1981. New calcareous nannofossil taxa from the Cretaceous of South East England. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte 1981, 633-640.
Forchheimer, S., Stradner, H., 1973. Scampanella, a new genus of Cretaceous nannofossils. Verhandlungen der Geologischen Bundesanstalt (Wien) 2, 286-289.
Perch-Nielsen, K., Franz, H. E., 1977. Lapideacassis and Scampanella, calcareous nannofossils from the Paleocene at sites 354 and 356, DSDP Leg 39, Southern Atlantic. Initial Reports of the Deep Sea Drilling Project 39, 849-862.
Wise, S. W., Wind, F. H., 1977. Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP Leg 36 drilling on the Falkland Plateau, south-west Atlantic sector of the Southern Ocean. Initial Reports of the Deep Sea Drilling Project 36, 269-491