Nannotax3 - ntax_cenozoic - Biscutum harrisonii

Citation: Biscutum harrisonii Varol, 1989

Synonyms:

Conococcolithus panis Edwards 1973 = Biscutum panis (Edwards) Edwards & Perch-Nielsen 1975 = Markalius panis (Edwards) Jiang & Gartner 1986 - this appears to be a senior synonym, and was described from the Danian [my interpretation - JRY 2020]
Biscutum castrorum Black 1959 - sensu Pospichal & Wise 1990. Biscutum castrorum * was described by Black from the Chalk and the holotype is a poor TEM, so this is not a satisfactory identification for the Danian species [my interpretation - JRY 2024, Bown et al. 2023]

Taxonomic discussion: Very similar Late Cretaceous coccoliths are commonly referred to Biscutum melaniae Gorka 1957, e.g. by Burnett (1997). These two species, B. melaniae (Cretaceous) and B. harrisonii (Danian) may be directly related, but to simplify cataloguing and to reflect typical usage we list them here as separate species.

Distinguishing features:
Parent taxon (Biscutum): Elliptical placoliths 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: Medium sized, broadly elliptical, bicyclic placolith with a closed central area. The birefringent tube cycle is narrow but conspicuous in XPL.

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

References:

Bown, P. R., Kim, H. & Gibbs, S. J. (2023). Danian calcareous nannofossil evolution and taxonomy with focus on sites from the North Atlantic Ocean (IODP Expedition 342, Sites U1403 and U1407). Journal of Nannoplankton Research. 41(2): 110-157. gs O

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

Bybell, L. M. & Self-Trail, J. (1995). Evolutionary, biostratigraphic and taxonomic study of calcareous nanofossils from a continuous Palaeocene-Eocene boundary section in New Jersey. U.S. Geological Survey, Professional Paper. 1554: 1-36. gs O

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 O

Edwards, A. R. (1973b). 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

Mai, H., von Salis, K., Willems, H. & Romein, A. J. T. (1997). Fossil coccospheres from the K/T boundary section from Geulhemmerberg, The Netherlands. Micropaleontology. 43: 281-303. gs

Perch-Nielsen, K. (1979). Calcareous nannofossil zonation at the Cretaceous/Tertiary boundary in Denmark. In, Birkelund, T. & Bromley, R. G. (eds) Proceedings Cretaceous-Tertiary Boundary Events Symposium, Copenhagen, 1. Copenhagen 115-135. gs O

Pospichal, J. J. & Bralower, T. J. (1992). Calcareous Nannofossils Across the Cretaceous/Tertiary Boundary, Site 761, Northwest Australian Margin. Proceedings of the Ocean Drilling Program, Scientific Results. 122: 735-752. gs

Pospichal, J. J. & Wise, S. W. (1990). Calcareous nannofossils across the K/T boundary, ODP hole 690C, Maud Rise, Weddell Sea. Proceedings of the Ocean Drilling Program, Scientific Results. 113: 515-532. 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

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

Missing or ambiguous references: ;

Comments (2)

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

30 June 2020 13:12

Jeremy Young(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

30 June 2020 14:27

Biscutum harrisonii

References:

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