|Daughter taxa (time control age-window is: 0-800Ma)|
|no prominent boss|
Thin, delicate discoaster with 30-50 rays joined along most of their length with simple ray tips.
Large to very large rosette-shaped discoasters; 16-35 rays joined along most of their length with simple ray tips.
Small to medium sized (4-10 µm) rosette-shaped discoasters with thickened central area; 20-26 rays joined along their length with simple, blunt ray tips.
Small (4-6 µm), rosette-shaped discoaster with raised central area; 20-30 rays joined along most of their length with simple ray tips.
Medium sized rosette-shaped discoasters; 9-16 rays joined along most of their length with simple broad ray tips.
7-13 tapering rays with simple rounded tips that radiate with little free length from a large circular central area.
|prominent boss on one side|
Large to very large rosette-shaped discoasters with a prominent boss on one side only; 12-24 rays joined along most of their length with simple ray tips.
Rosette-shaped discoaster with short narrow stem on one side; 9-13 rays joined along most of their length and which taper sharply to a simple pointed ray tip;
Rosette-shaped discoaster, bearing a tall, thin spine on one side; ca 12 rays, joined along most of their length with triangular terminations, .
Medium sized rosette-shaped discoasters with very large flaring boss on one side; 8-12 rays joined along most of their length with simple ray tips.
Flower shaped rosette discoaster with broad, flat, raised central area boss; 13-14 rays joined along ⅓-½ length and with broad rounded tips.
|prominent boss on both sides|
Large to very large rosette-shaped discoasters with prominent bosses on both sides; 9-16 rays joined along 1/2-2/3 length &typically curved.
Small to medium sized rosette-shaped discoaster with a narrow stem on one side and flared boss on the other; ca.14 rays with simple tips
Distinguishing features: Rosette shaped discoasters with little or no free rays (<1/3 length); typically >10 rays
Farinacci & Howe catalog pages:Search data:
|Metrics||Lith size: 4->22µm;|
Last occurrence (top): near top of Priabonian Stage (86% up, 34.4Ma, in Priabonian stage). Data source: Total of range of species in this database
First occurrence (base): near base of Thanetian Stage (8% up, 59Ma, in Thanetian stage). Data source: Total of range of species in this database
Plot of occurrence data:
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