Discorhabdus


Classification: Mesozoic -> Podorhabdales -> Biscutaceae -> Discorhabdus
Sister taxa: Biscutum, Discorhabdus, Similiscutum, Boletuvelum, Chiastella, Crucibiscutum, Gaarderella, Gephyrobiscutum, Helicorhabdus, Jimenezberrocosoia, Seribiscutum, 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 0-800Ma)
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 (3-5 µm), 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: Discorhabdus + * , Cenorbiculus * , Bidiscus *

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

Search data:
TagsLITHS: placolith, circular, CA: process, closed, V-UNITS: V-prominent, DETAILS: rim-bicyclic,
MetricsLith size: 3->8µm;
Sources: size range of included species
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Maastrichtian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Toarcian Stage (27% up, 180.4Ma, 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. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 34-85. gs :: ::

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

Noël, D. (1965). Sur les Coccolithes du Jurassique Européen et d'Afrique du Nord. Éditions du Centre National de la Recherche Scientifique, Paris. 1-209. gs :: ::


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Discorhabdus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 16-7-2020

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10387 Go to Archive.is to create a permanent copy of this page - citation notes



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