Polycostella parvistellatus


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

Distinguishing features: Small (<6 µm) form formed of 5 segments


Taxonomy:

Citation: Polycostella parvistellatus (Varol 1991) Varol & Bowman 2019
Rank: Species
Basionym: Micrantholithus? parvistellatus Varol 1991
Taxonomic discussion: Varol (1991) suggested that the species shows similarity to Polycostella.  The combination P. parvistellatus  was proposed by Bergen et al. 2014 but accoriding to Varol & Bowman (2019) the combination was not validly proposed since it did not meet the requirements of full citation of the basionmy of ICN Art 41.5.

Farinacci & Howe catalog pages: M. parvistellatus *

Distinguishing features: Small (<6 µm) form formed of 5 segments


Morphology:

Small (< 6.0 μm) nannoconid having five longitudinal ridges. The wall cycles are thin and low- angled, and the axial canal is very narrow. It is stellate in plan view and has sutures between the segments, which meet at the periphery of the vertices of the nannolith. It is strongly birefringent in plan view, but weakly birefringent or non-birefringent in side view.

Search data:
TagsLITHS: nannolith-radiate, pentagonal, star-shaped, cylindrical, CA: closed, CROSS-POLARS: T-prominent,
MetricsLith size: 4->6µm; Segments: 5->5;
Data source notes: original description & 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 Early Berriasian Substage (143.57-145.01Ma, top in Berriasian stage). Data source: Varol & Bowman 2019
First occurrence (base): within Late Tithonian Substage (145.01-147.72Ma, base in Tithonian stage). Data source: Varol & Bowman 2019

Plot of occurrence data:

References:

Bergen, J. A., Boesiger, T. M. & Pospichal, J. J. (2014). Low-latitude Oxfordian to Early Berriasian nannofossil biostratigraphy and its application to the subsurface of Eastern Texas. In, Hammes, U. & Gale, J. (eds) Geology of the Haynesville Gas Shale in East Texas and West Louisiana, U.S.A. American Association of Petroleum Geologists, Memoirs. 105: 69-102. gs

Varol, O. & Bowman, A. R. (2019). Taxonomic revision of selected Late Jurassic (Tithonian) calcareous nannofossils and the application of mobile mounting. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 291: 65-87. gs

Varol, O. (1991). New Cretaceous and Tertiary Calcareous Nannofossils. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 182: 211-237. gs


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Polycostella parvistellatus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 17-6-2021

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10660 Go to Archive.is to create a permanent copy of this page - citation notes



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