Schizosphaerella oblongata Worsley, 1971
The wall remains in constant extinction, with its optic axis (c‑axis) oriented perpendicular to the microscope stage, whereas the central area displays strong birefringence, showing 1st‑order white to yellow interference colours.
Large loxoliths consist of a granular central area surrounded by high walls and lacking any distal process. The central area may lie flush with the wall or rise above it to form a domed structure.
Thierstein, H. R., 1971. Tentative Lower Cretaceous Calcareous Nannoplankton Zonation. Eclogae Geologicae Helvetiae 64, 459-488.
Worsley, T. R., 1971. Calcareous nannofossil zonation of Upper Jurassic and Lower Cretaceous sediments from the Western Atlantic. In: Farinacci, A. (ed.), Proceedings of the Second Planktonic Conference Roma 1970. Edizioni Tecnoscienza, Rome vol. 2, pp. 1301-1321.