Daughter taxa (time control age-window is: 0-800Ma)![]() | ||||
| Alisphaera unicornis POL Distal cup entire, smooth | ||||
| Alisphaera gaudii POL Distal cup with two lenticular openings | ||||
| Canistrolithus valliformis POL Distal cup entire, with tubercles | ||||
| Polycrater sp. with lip-like borders Distal cup entire, with wide smooth borders | ||||
| Polycrater sp. minimum Distal cup entire, nannoliths very small (ca 0.2 µm) | ||||
| Polycrater sp. with slit Distal cup with notch on one edge | ||||
| Polycrater sp. ladle-like Distal cup incomplete, two petals normal, the other two reduced to a rod-like structure | ||||
| Polycrater sp. two petals modified two absent Distal cup incomplete, two petals reduced to a rod-like structure, the other two absent | ||||
| Polycrater sp. Specimens which cannot be assigned to established species | ||||
Distinguishing features:
Parent taxon (Alisphaeraceae): Heterococcoliths asymetric, arranged in meridional rows on coccosphere; V-unit forms flange, R-unit basal. Also nannolith phase "Polycrater" with quadrate aragonitic liths.
This taxon: Phase with quadrate, cup-like nannoliths
See also: Alisphaera ;Canistrolithus ;
Search data:| LITHS: nannolith-radiate, quadrate, CA: ca_conjunct, CSPH: equant, monomorphic, CROSS-POLARS: V-prominent, |
| Lith size: 0.3->1µm; Segments: 4->4; Coccosphere size: 5->16µm; |
Geological Range:
Last occurrence (top): Extant. Data source: Total of ranges of the species in this database
First occurrence (base): within No known fossil record modern (0.00-0.00Ma, base in "Holocene" stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
Cros, L. & Fortuño, J. -M. (2002). Atlas of northwestern Mediterranean coccolithophores. Scientia Marina. 66: 1-186. gs Manton, I. & Oates, K. (1980). Polycrater galapagensis gen. et sp. nov., a putative coccolithophorid from the Galapagos Islands with an unusual aragonitic periplast. British Phycological Journal. 15: 95-103. gs Supraha, L., Ljubesic, Z. & Henderiks, J. (2018). Combination coccospheres from the Eastern Adriatic coast: New, verified and possible life-cycle associations. Marine Micropaleontology. 141: 23-30. gsReferences:

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Polycrater phase compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 13-10-2026
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=1059 Go to Archive.is to create a permanent copy of this page - citation notes |
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