Davidhakania saepes

Neochiastozygus saepes Perch-Nielsen, 1971b

This species of Davidhakania is characterised by a symmetrical diagonal cross, with its acute angle aligned along the short axis of the discolith. Its optical properties are consistent with those of the genus Davidhakania. This species exhibits extinction lines with a typical extinction angle of approximately 74° on the distal side and displays length-fast (−) elongation.

Two distinct size variations of Davidhakania saepes were observed, with forms greater than 6.0 μm restricted to NP4–NP5.

Davidhakania saepes differs from Davidhakania partingtonii, another species with a symmetrical crossbar, by the orientation of its acute angle, which is aligned along the short axis of the discolith. In contrast, Davidhakania partingtonii is aligned along the long axis. Additionally, Davidhakania saepes is distinguished from Davidhakania eosaepes and Davidhakania imbriei by possessing a symmetrical crossbar, whereas the latter species exhibit asymmetrical crossbars.

Perch-Nielsen, K. 1971d. Neue Coccolithen aus dem Paläozän von Dänemark, der Bucht von Biskaya und dem Eozän der Labrador See. Bulletin of the Geological Society of Denmark 21: 51-66.

Varol, O. 2025a. A practical guide to optical studies of calcareous nannofossils. Grzybowski Foundation Special Publication. 29: 1-222