Discoaster prepentaradiatus prepentaradiatus
Classification: ntax_cenozoic -> Discoasterales -> Discoasteraceae -> Discoaster -> D. pentaradiatus group -> Discoaster prepentaradiatus -> Discoaster prepentaradiatus prepentaradiatus
Sister taxa: D. prepentaradiatus prepentaradiatus, D. prepentaradiatus plautus, D. styzenii, D. trifolius
- Browning et al 2017 fig3-03.jpg
- Browning et al 2017 pl01 23.JPG
- Browning et al 2017 pl01 24.JPG
- Browning et al 2017 pl01 25.JPG
- Browning et al 2017 pl01 26.JPG
Citation: Discoaster prepentaradiatus ssp. prepentaradiatus Bukry & Percival 1971Rank: speciesSynonyms:
Taxonomic discussion: Subdividing prepentaradiatus into subspecies was introduced in Browning et al. (2017), however the name D. prepentaradiatus ssp. prepentaradiatus is an autonym and so retains the holotype and authorship of the original description. Separating the two morphotypes has obvious logic since they are quite distinct and it is dificult to adequately describe the species without explicitly describing the two forms. However, they have very similar ranges and intermediate speciemens occur, so they are unlikely to represent discrete biological species.
- D. prepentaradiatus - slender
Distinguishing features: Form with slender bifurcations
Farinacci & Howe catalog pages:
Morphology: Typically this form has long slender bifurcations diverging at an acute angle, relative slender rays and small central area. It superficially resembles D. pentaradiatus, but they can easily be distinguished by use of cross-polarised light; on D. pentaradiatus specimens the 5-rays behave as separate crystal units whereas on D. prepentaradiatus (and all other discoasters) the whole specimen behaves as one crystal unit.
The morphological data given here can be used on the advanced search page. See also these notes
|Tags||LITHS: nannolith-radiate, star-shaped, CROSS-POLARS: 1ou, V-prominent, |
|Metrics||Lith size: 0->0µm; |
Last occurrence (top): near top of NN10 zone (91% up, 8.4Ma, in Tortonian stage). Data source: Browning et al 2017
First occurrence (base): in mid part of NN9 zone (46% up, 10.1Ma, in Tortonian stage). Data source: Browning et al 2017
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
- (NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Discoaster prepentaradiatus
Browning, E., Bergen, J. A., Blair, S. A., Boesiger, T. M. & de Kaenel, E. (2017). Late Miocene to Late Pliocene taxonomy and stratigraphy of the genus Discoaster in the circum North Atlantic Basin: Gulf of Mexico and ODP Leg 154. Journal of Nannoplankton Research. 37(2-3): 189-214. gs V O