Lithastrinus stradneri Perch-Nielsen 1973
Emended Diagnosis: Circular to sub-circular, tubular calcareous nannofossils feature a double-storey, unicyclic wall, with each storey comprising twelve to forty strongly sinistrally imbricated segments. The two walls are often unequal in height, and a disjunct double-layered amedian diaphragm is extended near the intersection. The outer surface is frequently adorned with both lateral and longitudinal ornamentation. The short wall side is regarded as distal based on the distribution of interference colours. In XPL, with a gypsum plate inserted, blue interference colours align with the horizontal axis of the taxa on the diaphragm.
Optical Properties: The optical properties of Perchnielsenella align with those observed in the family Perchnielsenaceae.
Perch-Nielsen, K. 1973c. Neue Coccolithen aus dem Maastrichtien von Danemark, Madagaskar und Agypten. Bulletin of the Geological Society of Denmark. 22: 306-333.
Watkins, D. K. & Bowdler, J. L. 1984. Cretaceous calcareous nannofossils from Deep Sea Drilling Project Leg 77, southeast Gulf of Mexico. Initial Reports of the Deep Sea Drilling Project. 77: 649-674.