Neochiastozygus perfectus Perch-Nielsen, 1971d
Optical Properties: The outer wall remains in constant extinction, while the inner wall often exhibits intense white interference colours and length-fast (−) elongation in the plan view. In this orientation, the inner wall predominates over the outer wall. In the side view, the outer wall displays a first-order whitish-grey interference colour and length-fast (−) elongation. In contrast, the inner wall, with first-order intense white interference colour, exhibits length-slow (+) elongation.
This elliptical discolith consists of a dextrally imbricated outer wall, a sinistrally imbricated inner wall of similar height, and a central area spanned by a crossbar. Species of Neochiastozygus are distinguished by the construction and the orientation of the central crossbar and its arms.
Neochiastozygus differs from Davidhakania in having a dextrally imbricated outer wall and a sinistrally imbricated inner wall of equal height. In contrast, Davidhakania has a protolith outer wall and a very low sinistrally imbricated inner wall.
Additionally, Neochiastozygus is distinguished from Chiastozygus by the presence of an inner wall, which is absent in Chiastozygus.
Neochiastozygus is differentiated from Helicolithus in the construction of the outer wall. Neochiastozygus has a dextrally imbricated outer wall, whereas s possesses a sinistrally imbricated outer wall.
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.