Nannotax3 - ntax_mesozoic - Biscutum thurowii Nannotax3 - ntax_mesozoic - Biscutum thurowii

Biscutum thurowii


Classification: ntax_mesozoic -> Podorhabdales -> Biscutaceae -> Biscutum -> Biscutum thurowii
Sister taxa: B. constans, B. ellipticum ⟩⟨ B. coronum, B. dekaenelii, B. magnum, B. melaniae ⟩⟨ B. arrogans, B. asymmetricum, B. boletum, B. dissimilis, B. zulloii ⟩⟨ B. hattneri, B. notaculum, B. virginica ⟩⟨ B. gaultensis, B. thurowii ⟩⟨ B. davyi, B. depravatum, B. dorsetensis, B. dubium, B. erismatum, B. grande, B. intermedium, B. planum, B. profundum, B. sp.

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: Small (3-5 µm), with a small central area lined with blocks and two central-area perforations separated by a birefringent transverse bar aligned with the short ellipse axis.


Taxonomy:

Citation: Biscutum thurowii Burnett, 1997
taxonomic rank: Species
Taxonomic discussion: This morphotype was initially identified by Burnett 1997 as Biscutum gartneri Gartner 1967, based on similarity to specimens from Black 1971.

Farinacci & Howe catalog pages: B. thurowii *

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: Small (3-5 µm), with a small central area lined with blocks and two central-area perforations separated by a birefringent transverse bar aligned with the short ellipse axis.


Morphology:

Distinguished from other species of Biscutum by the blocky lining to the central area, and the bar separating the two distinct perforations. 

Search data:
LITHS: placolith, elliptical, CA: bar, ca_disjunct, CROSS-POLARS: R-prominent, V-prominent, rim-bicyclic,
Lith size: 3->5µm;
Data source notes: holotype +/- 1µm
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within Early Cenomanian Substage (96.24-100.50Ma, top in Cenomanian stage). Data source: Burnett 1998
First occurrence (base): within Late Albian Substage (100.50-107.59Ma, base in Albian stage). Data source: Burnett 1998

Plot of occurrence data:

References:

Burnett, J. A. (1997c). New species and new combinations of Cretaceous nannofossils and a note on the origin of Petrarhabdus (Deflandre) Wise & Wind. Journal of Nannoplankton Research. 19(2): 133-146. gs

Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 132-199. gs O

Gale, A. S., Kennedy, W. J., Burnett, J. A., Caron, M. & Kidd, B. E. (1996). The Late Albian to Early Cenomanian succession at Mont Risou, near Rosans (Drôme, SE France): an integrated study (ammonites, inoceramids, planktonic foraminifera, nannofossils, oxygen and carbon isotopes). Cretaceous Research. 17: 515-606. gs

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Biscutum thurowii compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 16-10-2024

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