Nannotax3 - ntax_mesozoic - Tubodiscus verenae

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) Tubodiscus with broad, high collar cycle that is highly birefringent (yellow-orange) in XPL; often seen in side view.

Citation: Tubodiscus verenae Thierstein, 1973

Distinguished from all other tubodiscids by it high collar cycle. This species has only rarely been reported from boreal latitdues, but in tethyan sections it has been used biostratigraphically, since Thierstein (1973) reported that it was restricted to the Valanginian. Applegate and Bergen (1988), however, recorded this species rarely but consistently into the Upper Hauterivian of ODP Site 638.

Geological Range:
Notes: Bown et al. 1998 (fig 5.2) indicate that the top of T. verenae inthe Boreal Realm is significantly higher than the top of consistent T. verenae in the Tethyan Realm
Last occurrence (top): in upper part of BC10 zone (70% up, 128.6Ma, in Hauterivian stage). Data source: Bown et al. 1998 (fig 5.2)
First occurrence (base): within Late Berriasian Substage (137.70-139.90Ma, base in Berriasian stage). Data source: Bown et al. 1998

References:

Aguado, R. et al. (2018). A new record of the Weissert episode from the Valanginian succession of Cehegín (Subbetic, SE Spain): bio- and carbon isotope stratigraphy. Cretaceous Research. 92: 122-137. gs

Applegate, J. L. & Bergen, J. A. (1988). Cretaceous calcareous nannofossil biostratigraphy of sediments recovered from the Galicia Margin, ODP Leg 103. Proceedings of the Ocean Drilling Program, Scientific Results. 103: 293-348. gs O

Bown, P. R. (1992). New calcareous nannofossil taxa from the Jurassic/Cretaceous boundary interval of Sites 765 and 261, Argo Abyssal Plain. Proceedings of the Ocean Drilling Program, Scientific Results. 123: 369-379. gs

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

Covington, J. M. & Wise, S. W. (1987). Calcareous nannofossil biostratigraphy of a Lower Cretaceous deep-sea fan complex: Deep Sea Drilling Project Leg 93 Site 603, lower continental rise off Cape Hatteras. Initial Reports of the Deep Sea Drilling Project. 93: 617-660. gs O

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 O

Thierstein, H. R. (1973). Lower cretaceous calcareous nannoplankton biostratigraphy. Abhandlungen der Geologischen Bundesanstalt. 29: 3-52. gs

Tubodiscus verenae

References:

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