Distinguishing features: Parent taxon (Biscutaceae): Regular placoliths; rim broad, central area relatively narrow, with variable central structures.
The distal shield is formed from V-units and the proximal shield and tube cycle are formed from R-units. This taxon: Circular, shields broad, usually without a prominent inner tube cycle; central-area typically narrow, may contain a spine.
Daughter taxa (time control age-window is: 0-800Ma)
Discorhabdus corollatus Small Discorhabdus with narrow central area from which a tall, narrow spine protrudes.
Discorhabdus criotus 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.
Discorhabdus hannibalis 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.
Discorhabdus ignotus Small to medium-sized Discorhabdus with closed central area that may or may not contain a spine.
Distinguishing features: Parent taxon (Biscutaceae): Regular placoliths; rim broad, central area relatively narrow, with variable central structures.
The distal shield is formed from V-units and the proximal shield and tube cycle are formed from R-units. This taxon: Circular, shields broad, usually without a prominent inner tube cycle; central-area typically narrow, may contain a spine.
Lith size: 3->8µm; Data source notes: 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 Danian 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:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Neptune data: This is a higher taxon page so Neptune data is not plotted. See also: customisable plot Parent: Biscutaceae
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. gsO
Bown, P. R. & Young, J. R. (1997). Mesozoic calcareous nannoplankton classification. Journal of Nannoplankton Research. 19(1): 21-36. gsVO
Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 132-199. gsO
Noël, D. (1965). Sur les Coccolithes du Jurassique Européen et d'Afrique du Nord. Essai de classification des coccolithes fossiles. Éditions du Centre National de la Recherche Scientifique, Paris. 1-209. gs
Discorhabdus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 31-3-2023
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