Nannotax3 - ntax_mesozoic - Tubodiscus jurapelagicus

Distinguishing features:
Parent taxon (Tubodiscus): Tubodiscids with high and birefringent proximal collar cycle and wide central-area. Rim image is clearly bicyclic in XPL.
This taxon: Large (8-16 µm) with wide central area. Inner and outer rim cycles of similar width.

Citation: Tubodiscus jurapelagicus (Worsley, 1971) Roth, 1973

Basionym: Watznaueria jurapelagicus Worsley, 1971

Synonyms:

Tubodiscus parvus Street 1999, p. 146 [only proposed in an unpublished PhD thesi so a nomen nudum]

Similarly proportioned to M. pemmatoidea but is easily distinguished in the LM by its flaring collar, and the lack of ornament on its distal shield.

Geological Range:
Last occurrence (top): within Barremian Stage (121.40-126.50Ma, top in Barremian stage). Data source: Bown et al. 1998
First occurrence (base): within Late Berriasian Substage (137.70-139.90Ma, base in Berriasian stage). Data source: Bown et al. 1998

References:

Bown, P. R. & Concheyro, A. (2004). Lower Cretaceous calcareous nannoplankton from the Neuquen Basin, Argentina. In, Villa, G., Lees, J. A. & Bown, P. R. (eds) Calcareous Nannofossil Palaeoecology and Palaeocenographic Reconstructions, Proceedings of the INA9 conference, Parma 2002. Marine Micropaleontology . 52(1-4): 51-84. gs

Bown, P. R. (2005c). Early to Mid-Cretaceous Calcareous Nannoplankton from the Northwest Pacific Ocean, Leg 198, Shatsky Rise. Proceedings of the Ocean Drilling Program, Scientific Results. 198: 1-82. gs O

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

Bralower, T. J., Monechi, S. & Thierstein, H. R. (1989). Calcareous nannofossil zonation of the Jurassic-Cretaceous boundary interval and correlation with the geomagnetic polarity timescale. Marine Micropaleontology. 14: 153-235. gs

Roth, P. H. (1973). Calcareous nannofossils: Leg 17 of the Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project. 17: 695-795. gs O

Worsley, T. R. (1971). Calcareous nannofossil zonation of Upper Jurassic and Lower Cretaceous sediments from the Western Atlantic. In, Farinacci, A. (ed.) Proceedings of the Second Planktonic Conference Roma 1970. Edizioni Tecnoscienza, Rome 2: 1301-1321. gs O

Tubodiscus jurapelagicus

References:

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