Daughter taxa (time control age-window is: 0-800Ma)![]() | |||||
D. brouweri and variants | |||||
![]() | ![]() | ![]() | Discoaster triradiatus Symmetric 3-rayed variety of D. brouweri. | ||
![]() | ![]() | Discoaster tamalis Symmetric 4-rayed variety of D. brouweri. | |||
Discoaster alyssae Asymmetric 4-rayed variety of D. brouweri | |||||
![]() | ![]() | Discoaster asymmetricus Asymmetric 5-rayed variety of D. brouweri. | |||
![]() | Discoaster brouweri Ray tips non-bifurcate but with marked proximal extensions giving it a distinctive concavo-convex form. | ||||
Distinctive species | |||||
![]() | Discoaster altus 6 rayed with complanate rays; very large stellate proximal boss; and small distal boss. | ||||
![]() | Discaster mexicanus Compact nannolith formed of six stubby rays with similar overall shape to C. coalitus but lacking the basket-like structure. | ||||
![]() | ![]() | Discoaster calcaris 6-rayed with asymmetric ray tips; one bifurcation extended proximally | |||
Species with 6 flat rays and simple terminations | |||||
![]() | Discoaster braarudii Similar to D. brouweri but ray tips simple, without proximal extensions. | ||||
![]() | Discoaster neorectus Very large (>20µm), flat discoaster, with simple ray tips. | ||||
![]() | Discoaster dennei Flat and with simple ray terminations, medium to large. | ||||
![]() | Discoaster formosus Flat, with simple ray terminations, tapering was and large central area. | ||||
Discoaster pliostellulus small 6-rayed discoaster with stubby arms. | |||||
Discoaster brouweri-like preservational morphotypes poorly preserved 6-rayed discoasters without bifurcations |
Taxonomy:
Distinguishing features:
Parent taxon (Discoaster): Radiate nannoliths with each ray formed of a discrete crystal-unit, with the c-axes perpendicular to the nannolith surface.
This taxon: 6-rayed discoasters without bifurcations, and closely related forms with 3 to 5 rays.
Farinacci & Howe catalog pages:
Search data:
Lith size: 5->30µm; |
Geological Range:
Notes: This group is characteristic of the Late Miocene and Pliocene but the first appearance of the group is not of much value since it is gradational with disolution specimens resembling D. brouweri can be found in older sediments.
Last occurrence (top): at top of NN18 zone (100% up, 1.9Ma, in Gelasian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within Neogene Period (2.59-23.03Ma, base in Aquitanian stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
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 de Kaenel, E., Bergen, J. A., Browning, E., Blair, S. A. & Boesiger, T. M. (2017). Uppermost Oligocene to Middle Miocene Discoaster and Catinaster taxonomy and stratigraphy in the circum North Atlantic Basin: Gulf of Mexico and ODP Leg 154. Journal of Nannoplankton Research. 37(2-3): 215-244. gs O Young, J. R. (1998). Neogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 225-265. gs References:
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D. brouweri group compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 6-12-2023
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=419 Go to Archive.is to create a permanent copy of this page - citation notes |
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