Cryptococcolithus takayamae Gartner, 1992 syn. Birkelundia mediaperforatus Varol, 1991
Elliptical placolith having non-birefringent single cycle proximal and distal shields. The central area is spanned by a non-birefringent porous mesh which is best seen in the Phase Contrast setting.
Cryptococcolithus differs from the elliptical species of Calcidiscus Kamptner (1950) by having a non-birefringent proximal shield [arguably faintly birefringent].
Gartner, S., (1992): Miocene nannofossil chronology in the North Atlantic, DSDP Site 608. - Marine Micropaleontology. 18: 307-331.
Kamptner, E., (1950): Über den submikroskopischen Aufbau der Coccolithen. - Anzeiger der Österreichische Akademie der Wissenschaften, Mathematische-Naturwissenschafliche Klasse, Wien. 87: 152-158.
Varol, O., (1991): New Cretaceous and Tertiary Calcareous Nannofossils. - Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 182: 211-237.