Nannotax3 - ntax_cenozoic - Alisphaera unicornis POL Nannotax3 - ntax_cenozoic - Alisphaera unicornis POL

Alisphaera unicornis POL

Classification: ntax_cenozoic -> Coccolith families inc sed -> Alisphaeraceae -> Polycrater phase -> Alisphaera unicornis POL
Sister taxa: A. unicornis POL, A. gaudii POL, C. valliformis POL, P. sp. with lip-like borders, P. sp. minimum, P. sp. with slit, P. sp. ladle-like, P. sp. two petals modified two absent, P. sp.


Citation: Alisphaera unicornis Manton & Oates, 1980 POL
taxonomic rank: Species
Variants: Cros & Fortuño 2002 described and illustrated two other morphologically simple forms of Polycrater:"
These may prove to intraspecific varaints or may be associated with other Alisphaera species.

Distinguishing features:
Parent taxon (Polycrater phase): Phase with quadrate, cup-like nannoliths
This taxon: Distal cup entire, smooth

Farinacci & Howe catalog pages: P. galapagensis *


Typical form, coccoliths are simple cones without holes, notches or extensions.

Biology & life-cycles

Supraha et al. (2018) published a single combination coccosphere image showing Alisphaera unicornis heterococcoliths associated with Polycrater galapagenis nannoliths. This confirmed the life cycle association between Polycrater and Alisphaera previously documented by Cros et al. (2000) and so allowed revision of the taxonomy. However, it should be noted that more species have been described in Alisphaera than in Polycrater, so it is possible that several species of Alisphaera may have virtually identical Polycrater-type nannoliths.

See also: Alisphaera unicornis - alternate life-cycle phase;

Search data:
LITHS: nannolith-radiate, quadrate, CA: ca_conjunct, closed,
CSPH: equant, monomorphic, CROSS-POLARS: V-prominent,
Lith size: 0.5->0.7µm; Segments: 4->4; Coccosphere size: 9->14µm; Liths per sphere: 600->1000
Data source notes: csph & lith length from Cros & Fortuño 2002 & illustrated specs
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): Extant. Data source: present in the plankton (Young et al. 2003)
First occurrence (base): within No known fossil record modern (0-0Ma, base in "Holocene" stage). Data source: [JRY rough estimate]

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. gs

Thomsen, H. A. & Buck, K. R. (1998). Nanoflagellates of East Pacific coastal Waters: Morphology, taxonomy, and biogeography of weakly calcified coccolithophorids (Prymnesiophyceae). Cryptogamie Algologie. 19: 29-48. gs

Young, J. R., Geisen, M., Cros, L., Kleijne, A., Probert, I. & Ostergaard, J. B. (2003). A guide to extant coccolithophore taxonomy. Journal of Nannoplankton Research. S1: 1-132. gs


Alisphaera unicornis POL compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 10-12-2023

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Josue Millan(US)

Dr Jelena Godrijan micrograph.