Distinguishing features:
Parent taxon (Biscutum): Elliptical with broad shields with or without a prominent inner tube cycle; the central-area may be imperforate or narrow and vacant or spanned by a simple structure (plate, cross or bar).
This taxon: Normally elliptical Biscutum with relatively narrow shields and open central area spanned by cross bars slightly rotated from axial. Unicyclic image in XPL.
Taxonomy:
Farinacci & Howe catalog pages: A. depravatus *
Distinguishing features:
Parent taxon (Biscutum): Elliptical with broad shields with or without a prominent inner tube cycle; the central-area may be imperforate or narrow and vacant or spanned by a simple structure (plate, cross or bar).
This taxon: Normally elliptical Biscutum with relatively narrow shields and open central area spanned by cross bars slightly rotated from axial. Unicyclic image in XPL.
Search data:
LITHS: placolith, elliptical, CA: ca_disjunct, process, diagonal cross, CROSS-POLARS: rim-unicyclic, V-prominent, |
Lith size: 5->7µm; Data source notes: original description |
Geological Range:
Last occurrence (top): within Middle Oxfordian Substage (156.60-159.40Ma, top in Oxfordian stage). Data source: Bown & Cooper 1998
First occurrence (base): within Aalenian Stage (170.90-174.70Ma, base in Aalenian stage). Data source: Bown & Cooper 1998
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 Bown, P. R. (1987a). Taxonomy, evolution, and biostratigraphy of Late Triassic-Early Jurassic calcareous nannofossils. Special Papers in Palaeontology. 38: 1-118. gs Grün, W. & Zweili, F. (1980). Das kalkige Nannoplankton der Dogger-Malm-Grenze im Berner Jura bei Liesberg (Schweiz). Jahrbuch der Geologischen Bundesanstalt. 123: 231-341. gs van Heck, S. E. (1990). The ICBN: Things you need to know - 1. INA Newsletter. 12(1): 19-20. gs Missing or ambiguous references: ; References:
Biscutum depravatum compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 20-9-2024
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10075 Go to Archive.is to create a permanent copy of this page - citation notes |
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