Nannotax Enabling nannofossil research

Description: Large rod-shaped holococcolith with small basal disk.

Remarks: In well-preserved material (E.g. Bown 2005) it can be seen that these are cavate holococcoliths, i.e. they have an internal cavity. Usually howevr with overgrowth this cavitiy is filled and the holococcolith develops nirregular form.

Range: Palaeogene to NN1, rarely NN2 (see de Kaenel and Villa, 1996).

Original description:

Synonyms (list from Aubry 1988):

• Isthmolithus claviformis Bronnimann & Stradner 1960
• Lucianorhabdus dispar Stradner 1961
• Pseudozygrhablithus altus Haq 1971
• Pseudozygrhablithus latus Haq 1971
• Pseudozygrhablithus comprimus Haq 1971
• Rhabdosphaera semiformis Bramlette & Sullivan 1961
• Sujkowskiella enigmatica Hay Mohler & Wade 1966

Of these I. claviformis, S. enigmatica and R. semiformis were all based on isolated half or quarter specimens of Z. bijugatus.