Polycostella beckmannii


Classification: ntax_mesozoic -> Braarudosphaerales -> Transitional genera -> Polycostella -> Polycostella beckmannii
Sister taxa: P. senaria, P. infans, P. beckmannii, P. parvistellatus, P. sp.

Distinguishing features: Small (<6 µm), globular, formed of 6-8 segments.


Taxonomy:

Citation: Polycostella beckmannii Thierstein, 1971
Rank: Species
Taxonomic discussion: de Kaenel & Bergen (1996) noted that detached spines of Conusphaera mexicana subsp. minor were verysimilar to P. bckmannii and suggested that P. beckmannii might prove to be a preservational variant of Conusphaera  

Farinacci & Howe catalog pages: P. beckmannii *

Distinguishing features: Small (<6 µm), globular, formed of 6-8 segments.

Search data:
TagsLITHS: nannolith-radiate, circular, cylindrical, CA: closed, CROSS-POLARS: T-prominent,
MetricsLith size: 3.5->6µm; Segments: 6->8;
Data source notes: original description
The morphological data given here can be used on the advanced search page. See also these notes

See also: Conusphaera mexicana subsp. minor - possibly source of P. beckmannii;

Geological Range:
Last occurrence (top): within Tithonian Stage (145.01-152.06Ma, top in Tithonian stage). Data source: Bown & Cooper 1998
First occurrence (base): at base of NJT15b subzone (0% up, 149.8Ma, in Tithonian stage). Data source: Casellato 2010, fig16 - zonal marker

Plot of occurrence data:

References:

Bown, P. R. & Cooper, M. K. E. (1998). Jurassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 34-85. gs

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

Casellato, C. E. (2010). Calcareous nannofossil biostratigraphy of Upper Callovian - Lower Berriasian successions from the Souhern Alps, North Italy. Rivista Italiana di Paleontologia e Stratigrafia. 116(3): 357-404. gs V O

Thierstein, H. R. (1971). Tentative Lower Cretaceous Calcareous Nannoplankton Zonation. Eclogae Geologicae Helvetiae. 64: 459-488. gs V O


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Polycostella beckmannii compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 18-5-2021

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10924 Go to Archive.is to create a permanent copy of this page - citation notes



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