Nannotax3 - ntax_mesozoic - Watznaueria biporta

Large (8-12 µm) Watznaueria with two well-defined pores separated by a conjunct transverse bar.

Citation: Watznaueria biporta Bukry, 1969

Large (8-12 µm) Watznaueria with two well-defined pores separated by a conjunct transverse bar.

Morphology:

Both Black (1973) and Bukry (1969) illustrate specimens apparently with the remains of a grill in the pores.

It is noteworthy that all the illustrated specimens are genuinely large - typically 9-11 µm long, whilst W. barnesiae is rarely more than 8 µm. On the othe hand it is a very sporadically distributed form. Possibly this is a morphotype which develops when W. barnesiae gets very large. [my interpretation - JRY 2020]

Geological Range:
Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Maastrichtian stage). Data source: Lees & Bown 2005 - consistently present to end Cret
First occurrence (base): within Tithonian Stage (145.01-152.06Ma, base in Tithonian stage). Data source: oral comms during Jurassic workshop, Lyon 2016 and Neptune records

References:

Black, M. (1973). British Lower Cretaceous Coccoliths. I-Gault Clay (Part 2). Palaeontographical Society Monograph. 127: 49-112. gs

Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Early Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 86-131. gs

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

Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 132-199. gs V O

Cepek, P. (1978). Mesozoic calcareous nannoplankton of the Eastern North Atlantic, Leg 41. Initial Reports of the Deep Sea Drilling Project. 41: 667-687. gs V O

Gale, A. S., Kennedy, W. J., Burnett, J. A., Caron, M. & Kidd, B. E. (1996). The Late Albian to Early Cenomanian succession at Mont Risou, near Rosans (Drôme, SE France): an integrated study (ammonites, inoceramids, planktonic foraminifera, nannofossils, oxygen and carbon isotopes). Cretaceous Research. 17: 515-606. gs

Grün, W. & Allemann, F. (1975). The Lower Cretaceous of Caravaca (Spain): Berriasian Calcareous Nannoplankton of the Miravetes Section (Subbetic Zone, Prov. of Murcia). Eclogae Geologicae Helvetiae. 68: 147-211. gs V O

Hardas, P. & Mutterlose, J. (2008). Calcareous nannofossil assemblages of Oceanic Anoxic Event 2 in the equatorial Atlantic: Evidence of an eutrophication event. Marine Micropaleontology. 66: 52-69. gs

Hattner, J. G. & Wise, S. W. (1980). Upper Cretaceous calcareous nannofossil biostratigraphy of South Carolina. South Carolina Geology. 24: 41-117. gs

Mai, H. (2001). New coccolithophorid taxa fom the Guelhemmerberg airshaft. Lower Paleocene, The Netherlands. Micropaleontology. 47: 144-154. gs

Thibault, N. (2010). Calcareous nannofossils from the boreal Upper Campanian- Maastrichtian chalk of Denmark. Journal of Nannoplankton Research. 31(1): 39-56. gs V O

Tags	LITHS: placolith, elliptical, CA: ca_conjunct, bar, CSPH: equant, monomorphic, CROSS-POLARS: rim-unicyclic, R-prominent,
Metrics	Lith size: 8->12µm; Data source notes: original description & illustrated specimens

Watznaueria biporta

References:

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