Polycostella infans


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

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


Taxonomy:

Citation: Polycostella infans (Bralower in Bralower et al., 1989) Varol & Bowman 2019
Rank: Species
Basionym: Nannoconus infans Bralower in Bralower et al., 1989
Synonyms:
Taxonomic discussion: Transferred to Polycostella by Varol & Bowman based on appearance in plan view. NB  Bralower et al. (1989) commented on the similarity of this species to P. beckmannii.

Farinacci & Howe catalog pages: N. infans * , H. geometricus *

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


Morphology: Minute to medium sized (1-6µm, typically 2-3µm) nannoconid with square, rectangular or oval outline and very narrow canal, in plan view formed of 6 segments. Wall cycles are flat.

Search data:
TagsLITHS: nannolith-radiate, star-shaped, cylindrical, polygonal, hollow, CA: closed, CROSS-POLARS: T-prominent,
MetricsLith size: 2->8µm; Segments: 6->6;
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 Early Berriasian Substage (143.57-145.01Ma, top in Berriasian stage). Data source: Bralower et al., 1989
First occurrence (base): at base of NJT16b subzone (0% up, 147.7Ma, in Tithonian stage). Data source: Casellato 2010, fig16 - zonal marker

Plot of occurrence data:

References:

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

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


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Polycostella infans 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=10754 Go to Archive.is to create a permanent copy of this page - citation notes



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