Watznaueria ovata

Watznaueria ovata Bukry, 1969

Elliptical species of Watznaueria are characterised by a relatively large subcircular to elliptical central opening devoid of internal structures. The width of the central opening is consistently less than that of the pelaga.

The shields, as well as the tube cycles, display first-order white interference colours with inclined extinction lines and length-fast (–) elongation. In distal view, the extinction angles are approximately 82° in the distal shield and about 72° in the tube cycles. The locking cycle remains in constant extinction, forming a narrow dim suture between the shield and tube cycle.

Watznaueria ovata differs from Watznaueria fossacincta in possessing a relatively larger central opening (>1.0 µm), whereas the latter has a smaller opening (<1.0 µm). In addition, extinction angles in the tube cycles and in the shields differ significantly between the two species.

Watznaueria ovata is further distinguished from Watznaueria coronata by its sub-circular to elliptical central opening, whereas the latter exhibits a narrow, elongate opening.

Black, M. 1971a. Coccoliths of the Speeton Clay and Sutterby Marl. Proceedings of the Yorkshire Geological Society 38: 381-424.

Bown, P. R. & Cooper, M. K. E. 1989b: New calcareous nannofossils from the Jurassic. Journal of Micropalaeontology 8: 91-96.

Bukry, D. 1969. Upper Cretaceous coccoliths from Texas and Europe. University of Kansas Paleontological Contributions, Articles 51 (Protista 2): 1-79.

Gartner, S., 1968. Coccoliths and related calcareous nannofossils from Upper Cretaceous deposits of Texas and Arkansas. University of Kansas Paleontological Contributions, Articles 48 (Protista 1), 1-56.