Biscutum harrisonii


Classification: ntax_cenozoic -> Mesozoic Survivors -> Biscutaceae -> Biscutum -> Biscutum harrisonii
Sister taxa: B. braloweri, B. castrorum, B. harrisonii, B. neocoronum, B. sp.

Taxonomy:

Citation: Biscutum harrisonii Varol, 1989
Rank: Species
Synonyms:
Taxonomic discussion: Has been considered a junior synonym of Biscutum melaniae Gorka 1957 - however, the holotype of B. melaniae is a very poor drawing and does not show the small bright central area characteristic of this speceis.

Distinguishing features: Medium sized, broadly elliptical, bicyclic placolith with a closed central area. The birefringent tube cycle is narrow but conspicuous in XPL.

Farinacci & Howe catalog pages: B. harrisonii * , C. panis *


Size: Holotype length 6.9 microns.

Search data:
TagsLITHS: placolith, elliptical, CA: closed,
CSPH: equant, elongated, monomorphic, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
MetricsLith size: 6->6µm;
Data source notes: lith size from illustrated specs
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NP9 zone (55.86-57.21Ma, top in Ypresian stage). Data source: Varol, 1989
First occurrence (base): within NP1 zone (65.47-66.04Ma, base in Danian stage). Data source: Varol, 1989

Plot of occurrence data:

References:

Edwards, A. R. & Perch-Nielsen, K. (1975). Calcareous nannofossils from the southern Southwest Pacific, Deep Sea Drilling Project, Leg 29. Initial Reports of the Deep Sea Drilling Project. 29: 469-539. gs V O

Edwards, A. R. (1973). Key species of New Zealand calcareous nannofossils. New Zealand Journal of Geology and Geophysics. 16: 68-89. gs

Jiang, M. -J. & Gartner, S. (1986). Calcareous nannofossil succession across the Cretaceous/Tertiary boundary in east-central Texas. Micropaleontology. 32(3): 232-255. gs

Varol, O. (1989c). Palaeocene calcareous nannofossil biostratigraphy. In, Crux, J. A. & van Heck, S. E. (eds) Nannofossils and their applications: Proceedings of the 2nd INA Conference, London 1987. British Micropalaeontological Society Publication Series. 265-310. gs V O

Varol, O. (1998). Palaeogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 200-224. gs

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Biscutum harrisonii compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 23-1-2021

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=83 Go to Archive.is to create a permanent copy of this page - citation notes
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Jean Self-Trail

Jeremy, you say that Jiang & Gartner 1986 called B. harrisonii by the name B. panis. They actually made a new combination of Markalius panis

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Jeremy Young (Tonbridge, UK)

Hi Jean

Thanks for pointing out that mistake. It took a bit of searching but the combination was in fact proposed in a plate caption in Edwards & Perch-Nielsen 1975. I have updated the page now but what do you think, is there just one Danian Biscutum with a small central area - and what should it be called?

Jeremy

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