Watznaueria prionocycla

Watznaueria prionocycla Varol, in prep.

Large, subcircular species (10.0–13.0 µm) of Watznaueria, with distal and proximal shields of approximately equal size, a broad inner tube cycle completely closing the central area, and a narrow, serrated outer tube cycle readily observable under all illumination settings. The tube cycles are wider than the shields.

From Latin prion, saw and Greek kyklos, cycle, referring to the saw-like (serrated) morphology of the outer tube cycle.

In plan view under cross-polarised light, the shields and the outer tube cycle display first-order whitish-yellow interference colours, whereas the inner tube cycle exhibits first-order reddish-yellow interference colours. All structures show inclined extinction lines and length-fast (–) elongation.

In distal view, extinction angles are approximately 70° in the shields. These cannot be directly measured in the tube cycles due to the oblique orientation of their constituent segments; however, the apparent angle between extinction lines in the tube cycle is about 68°, corresponding to an obliquity of about 22°. The locking cycle exhibits interference colours, producing a transitional boundary between the tube cycle and shield.

Watznaueria prionocycla is distinguished from similarly sized, subcircular Watznaueria cauveryensis and the smaller Watznaueria angustoralis by its serrated and slightly distally raised outer tube cycle. In Watznaueria paenepelagica and Watznaueria angustoralis, extinction angles in the tube cycles can be directly measured at approximately 60° in distal view, whereas in Watznaueria prionocycla, they cannot be measured due to the oblique orientation of the constituent segments.

Lauer, G. 1972. Nannofossilen aus dem Wienerwald, In: Grün, Walter, et. al. Studien in der Unterkreide des Wienerwaldes: [Austria]. Jahrbuch der Geologischen Bundesanstalt, 115: 103–186.

Reinhardt, P. 1964. Einige Kalkflagellaten-Gattungen (Coccolithophoriden, Coccolithineen) aus dem Mesozoikum Deutschlands. - Monatsberichteder Deutschen Akademieder Wissenschaftenzu Berlin. 6: 749-759.

Stover, L. E. 1966. Cretaceous coccoliths and associated nannofossils from France and the Netherlands. Micropaleontology 12(2): 133-167.