Nannotax3 - ntax_mesozoic - Tegumentum octiformis Nannotax3 - ntax_mesozoic - Tegumentum octiformis

Tegumentum octiformis


Classification: ntax_mesozoic -> Eiffellithales -> Eiffellithaceae -> Tegumentum -> Tegumentum octiformis
Sister taxa: T. lucidum, T. octiformis, T. stradneri, T. sp.

Distinguishing features:
Parent taxon (Tegumentum): Murolith (loxolith) coccoliths with a prominent inner rim cycle that is birefringent and conspicuous in cross-polarised light. This cycle is broader than the outer rim cycle. The central area is spanned by curving, diagonal cross-bars.
This taxon: A species of Tegumentum with a narrow inner rim cycle and figure-of-eight cross-bars which can be resolved in a single plane of focus in the LM.


Taxonomy:

Citation: Tegumentum octiformis (Köthe, 1981) Crux, 1989
taxonomic rank: Species
Basionym: Chiastozygus octiformis Köthe, 1981

Farinacci & Howe catalog pages: C. octiformis *

Distinguishing features:
Parent taxon (Tegumentum): Murolith (loxolith) coccoliths with a prominent inner rim cycle that is birefringent and conspicuous in cross-polarised light. This cycle is broader than the outer rim cycle. The central area is spanned by curving, diagonal cross-bars.
This taxon: A species of Tegumentum with a narrow inner rim cycle and figure-of-eight cross-bars which can be resolved in a single plane of focus in the LM.

Search data:
LITHS: murolith, elliptical, CA: ca_disjunct, diagonal cross, CROSS-POLARS: rim-bicyclic, R-prominent,
Lith size: 5->8µm;
Data source notes: illustrated specimens
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NC5d subzone (121.83-125.42Ma, top in Barremian stage). Data source: Bown et al. 1998
First occurrence (base): at base of BC8a subzone (0% up, 131.5Ma, in Hauterivian stage). Data source: Bown et al. 1998, fig 5.1

Plot of occurrence data:

References:

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

Crux, J. A. (1989). Biostratigraphy and palaeogeographical applications of Lower Cretaceous nannofossils from north-western Europe. In, Crux, J. A. & van Heck, S. E. (eds) Nannofossils and their applications: Proceedings of the 2nd INA Conference, London 1987. British Micropalaeontological Society Publication Series . 143-211. gs

Köthe, A. (1981). Kalkiges Nannoplankton aus dem Unter-Hauterivum bis Unter-Barremium der Tongrube Moorberg/ Sarstedt (Unter-Kreide, NW-Deutschland). Mitteilungen der geologischen Institut Universitat Hannover. 21: 1-95. gs

Varol, O. & Girgis, M. (1994). New taxa and taxonomy of some Jurassic to Cretaceous calcareous nannofossils. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 192: 221-253. gs


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Tegumentum octiformis compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-4-2024

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