Biscutum ignotum

Tremalithus ignotus Górka, 1957

The type specimen was examined by Reinhardt, and a lectotype of this species was subsequently designated by Reinhardt & Górka (1967). The species coordinates are given using the mechanical stage, as marked in Górka (1957) and Reinhardt & Górka (1967).

Calculated size of the lectotype: 4.0 µm; number of segments in the shield: 12-16.

In plan view under XPL, the shields are in constant extinction because the optic axis (c-axis) is perpendicular to the microscope stage, whereas the tube cycle displays a white interference colour and exhibits length-fast (–) elongation.

The circular placolith has distal and proximal shields composed of approximately 12–24 elements and a narrow tube cycle

Górka, H. 1957. Les Coccolithophoridés du Maestrichtien supérieur de Pologne. Acta Palaeontologica Polonica. 2: 239-284

Reinhardt, P. & Górka, H. 1967. Revision of some Upper Cretaceous Coccoliths from Poland and Germany. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 129(3): 240-256.