Discorhabdus


Classification: Mesozoic -> Podorhabdales -> Biscutaceae -> Discorhabdus
Sister taxa: Biscutum, Boletuvelum, Chiastella, Crucibiscutum, Discorhabdus, Gaarderella, Gephyrobiscutum, Helicorhabdus, Jimenezberrocosoia, Seribiscutum, Similiscutum, Sollasites,

Distinguishing features: Circular, shields broad, usually without a prominent inner tube cycle; central-area typically narrow, may contain a spine.


Daughter taxa: (blue => in age window 0-300Ma)
Discorhabdus with gaps between distal shield elements
Small Discorhabdus with narrow central area from which a tall, narrow spine protrudes.
Discorhabdus with a narrow, distal inner cycle, narrow/closed central area and distal shield sutures that kink near the shield's outer edge. Bicyclic rim image.
Small to very small, with two closely appressed shields; proximal shield is wider than the distal shield, protruding beyond it and is at least twice as thick as the distal shield in side view.
Small to medium-sized Discorhabdus with closed central area that may or may not contain a spine.
Placoliths with a tall flaring spine.
Medium to large Discorhabdus with closed central area.
Species with low broad open protrusion and reduced proximal shield,
Specimens not identified to species level

Taxonomy:

Citation: Discorhabdus Noël, 1965
Rank: Genus
Type species: Rhabdolithus patulus Deflandre, 1954.
Synonyms: Bidiscus Bukry 1969 - widely used in the literature
Cenorbiculus Burns 1976

Farinacci & Howe catalog pages: Bidiscus * Cenorbiculus * Discorhabdus + *

Distinguishing features: Circular, shields broad, usually without a prominent inner tube cycle; central-area typically narrow, may contain a spine.

Geological Range:
Last occurrence (top): within Maastrichtian Stage (66.04-72.05Ma, top in Maastrichtian stage). Data source: Total of range of species in this database
First occurrence (base): within Toarcian Stage (174.15-182.70Ma, base in Toarcian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Bown, P.R. & Cooper, M.K.E., (1998). Jurassic. In: Bown, P.R. (Editor), Calcareous nannofossil biostratigraphy. British Micropalaeontological Society Publication Series. Chapman & Hall, pp. 34-85.

Burnett, J.A., (1998). Upper Cretaceous. In: Bown, P.R. (Editor), Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publications Series. Chapman & Hall, London, pp. 132-199.

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


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Discorhabdus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 20-7-2018

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