Orastrum campanensis


Classification: Mesozoic -> Holococcoliths -> Common genera -> Orastrum -> Orastrum campanensis
Sister taxa: O. asarotum, O. campanensis, O. porosuturalis, O. perspicuum, O. robinsonii, O. colligatum, O. sp.,

Distinguishing features: Central plate of 4 blocks - one per quadrant


Taxonomy:

Citation: Orastrum campanensis (Cepek, 1970) Wind & Wise in Wise & Wind, 1977
Rank: Species
Basionym: Tetralithus campanensis Cepek, 1970
Notes & discussion: This species shows significant similarities to O. porosuturalis (Bukry 1969) and arguably is an overgrown form of it and so a junior synonym [my interpretation - JRY 2019]

Farinacci & Howe catalog pages: Tetralithus campanensis *

Distinguishing features: Central plate of 4 blocks - one per quadrant


Morphology remarks: In light microscope, O. campanensis is optically separated into four large, similar blocks divided by sinuous sutures and two small blocks that cap the axial ends of the central area. It is only weakly birefringent, but shows its greatest birefringence when oriented parallel to polarisers. The outer rim is inconspicuous in cross-polarized light. (Blair & Watkins 2009)

Geological Range:
Notes: FCO in Europe in UC13, basal Campanian (Burnett 1998). FO placed just below Santotian/Coniacian boundary by Blair & Watkins (2009)
Last occurrence (top): in upper part of UC15d subzone (70% up, 76.2Ma, in Campanian stage). Data source: Burnett 1998
First occurrence (base): within Santonian Stage (83.64-86.26Ma, base in Santonian stage). Data source: Burnett 1998

Plot of occurrence data:

  • (NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Orastrum

    References:

    Blair, S. A. & Watkins, D. K. (2009). High-resolution calcareous nannofossil biostratigraphy for the Coniacian/Santonian Stage boundary, Western Interior Basin. Cretaceous Research. 30(2): 367-384. gs

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

    Cepek, P. (1970). Zur Vertikalverbreitung von Coccolithen-Arten in der Oberkreide NW-Deutschlands. Geologisches Jahrbuch. 88: 235-264. gs

    Wise, S. W. & Wind, F. H. (1977). Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP Leg 36 drilling on the Falkland Plateau, south-west Atlantic sector of the Southern Ocean. Initial Reports of the Deep Sea Drilling Project. 36(269-491): -. gs


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    Orastrum campanensis compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 22-11-2019

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10823 Go to Archive.is to create a permanent copy of this page - citation notes



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