Neochiastozygus perfectus

Neochiastozygus perfectus Perch-Nielsen, 1971d

Neochiastozygus macilentus Bown, 2005

A species of Neochiastozygus characterised by a large central area spanned by a delicate symmetrical crossbar with arms divided into two halves. The crossbar typically forms an angle between 60° and 70° along the short axis and an obtuse angle along the long axis.

The narrow outer wall remains in constant extinction, whilst the inner wall exhibits first-order white interference colours with dextrogyre inclined extinction lines and length-fast (−) elongation on the distal side. The crossbar appears slightly dimmer in this orientation, with its arms exhibiting length-fast (−) elongation.

Bown, P. R. 2005d. Palaeogene calcareous nannofossils from the Kilwa and Lindi areas of coastal Tanzania (Tanzania Drilling Project 2003-4). Journal of Nannoplankton Research 27(1): 21-95.

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.