Biscutum dubium


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

Distinguishing features: Small, normally elliptical Biscutum with narrow central area. Bicyclic image in XPL.


Taxonomy:

Citation: Biscutum dubium (Noël, 1965) Grün in Grün et al., 1974
Rank: Species
Basionym: Palaeopontosphaera dubia Noël, 1965
Synonyms: Discorhabdus longicornis Medd 1979 [cf. Neptune database synonymy]

Farinacci & Howe catalog pages: Palaeopontosphaera dubia + + + * , Discorhabdus longicornis *

Distinguishing features: Small, normally elliptical Biscutum with narrow central area. Bicyclic image in XPL.


Morphology remarks: This name is primarily used in the Jurassic, but small Biscutum coccoliths are also a common feature of Cretaceous assemblages, where they tend to be called B. constans or B. ellipticum.

Geological Range:
Last occurrence (top): within Berriasian Stage (139.39-145.01Ma, top in Berriasian stage). Data source: Bown & Cooper 1998
First occurrence (base): within Early Toarcian Substage (178.24-182.70Ma, base in Toarcian stage). Data source: Bown & Cooper 1998

Plot of occurrence data:

  • Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
  • Note to users in China - the diagram may not plot unless you use a VPN since I use google services on the website. If this is a problem please contact me 谢谢.
  • Taxon plotted: Biscutum dubium, synonyms included - Biscutum dubium; Discorhabdus longicornis; Palaeopontosphaera dubia;
  • space-time plot :: Samples map :: Parent: Biscutum

    References:

    Barnard, T. & Hay, W. W. (1974). On Jurassic coccoliths: A tentative zonation of the Jurassic of Southern England and North France. Eclogae Geologicae Helvetiae. 67(3): 563-585. gs

    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

    Bown, P. R. (1987a). Taxonomy, evolution, and biostratigraphy of Late Triassic-Early Jurassic calcareous nannofossils. Special Papers in Palaeontology. 38: 118-. gs

    Crux, J. A. (1987b). Early Jurassic calcareous nannofossil biostratigraphic events. Newsletters on Stratigraphy. 17: 79-100. gs

    Crux, J. A. (1987a). Concerning dimorphism in Early Jurassic coccoliths and the origin of the genus Discorhabdus Noël 1965. Abhandlungen der Geologischen Bundesanstalt. 39: 51-55. gs

    de Kaenel, E. & Bergen, J. A. (1993). New Early and Middle Jurassic coccolith taxa and biostratigraphy from the eastern proto-Atlantic (Morocco, Portugal and DSDP Site 547B). Eclogae Geologicae Helvetiae. 86(861-907): -. gs

    de Kaenel, E. & Bergen, J. A. (1996). Mesozoic calcareous nannofossil biostratigraphy from sites 897, 899, and 901, Iberia Abyssal Plain: New biostratigraphic evidence. Proceedings of the Ocean Drilling Program. Scientific Results. 149: 27-59. 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

    Grün, W., Prins, P. & Zweili, F. (1974). Coccolithophoriden aus dem Lias epsilon von Holzmaden (Deutschland). Neues Jahrbuch für Geologie und Paläontologie Abhandlungen. 147: 294-328. gs

    Medd, A. W. (1979). The Upper Jurassic coccoliths from the Haddenham and Gamlingay boreholes (Cambridgeshire, England). Eclogae Geologicae Helvetiae. 72: 19-109. gs

    Noël, D. (1965). Sur les Coccolithes du Jurassique Européen et d'Afrique du Nord. Éditions du Centre National de la Recherche Scientifique, Paris. -. gs

    Noël, D. (1973). Nannofossiles calcaires de sédiments jurassiques finement laminés. Bulletin du Muséum National d'Histoire Naturelle. 3e serie, 75: 95-156. gs

    Rood, A. P., Hay, W. W. & Barnard, T. (1971). Electron Microscope Studies of Oxford Clay Coccoliths. Eclogae Geologicae Helvetiae. 64: 245-272. gs

    Rood, A. P., Hay, W. W. & Barnard, T. (1973). Electron microscope studies of Lower and Middle Jurassic coccoliths. Eclogae Geologicae Helvetiae. 66: 365-382. gs

    Varol, O. & Girgis, M. (1994). New taxa and taxonomy of some Jurassic to Cretaceous calcareous nannofossils. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen. 192: 221-253. gs

    Wise, S. W. (1983). Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP Leg 71 in the Falkland Plateau region, Southwest Atlantic Ocean. Initial Reports of the Deep Sea Drilling Project. 71: 481-550. gs


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    Biscutum dubium compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 9-12-2019

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10078 Go to Archive.is to create a permanent copy of this page - citation notes



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