arrayname: original
Distinguishing features:
Parent taxon (Polycostella): Globular and stellate nannoliths formed of 5-8 segments of stacked elements. Nannoconus-like in side view.
This taxon: Small (<6 µm), globular, formed of 6-8 segments.
Taxonomy:
Farinacci & Howe catalog pages: P. beckmannii *
Distinguishing features:
Parent taxon (Polycostella): Globular and stellate nannoliths formed of 5-8 segments of stacked elements. Nannoconus-like in side view.
This taxon: Small (<6 µm), globular, formed of 6-8 segments.
Search data:
LITHS: nannolith-radiate, circular, cylindrical, CA: closed, CROSS-POLARS: T-prominent, |
Lith size: 3.5->6µm; Segments: 6->8; Data source notes: original description |
See also: Conusphaera mexicana subsp. minor - possibly source of P. beckmannii;
Geological Range:
Last occurrence (top): within Tithonian Stage (143.10-149.24Ma, top in Tithonian stage). Data source: Bown & Cooper 1998
First occurrence (base): at base of NJT15b subzone (0% up, 147Ma, in Tithonian stage). Data source: Casellato 2010, fig16 - zonal marker
Plot of occurrence data:
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 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 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 O Thierstein, H. R. (1971). Tentative Lower Cretaceous Calcareous Nannoplankton Zonation. Eclogae Geologicae Helvetiae. 64: 459-488. gs OReferences:
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Polycostella beckmannii compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 21-4-2025
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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