Alisphaera


Classification: Coccolithophores -> Coccolith families inc sed -> Alisphaeraceae -> Alisphaera
Sister taxa: Alisphaera, Canistrolithus, Polycrater,

Daughter taxa: (blue => in age window 0-800Ma) Granddaughter taxa
distal flange with sub-vertical extension

distal flange with wing-like extension

distal flange with spike-like protrusion formed from a single element, or smooth

Specimens which cannot be assigned to established species

Taxonomy:

Citation: Alisphaera Heimdal, 1973
Rank: Genus
Type species: Acanhoica ordinata Kampnter 1941
Notes & discussion: The species-level taxonomy of the genus was reviewed by Jordan & Chamberlain (1993) and by Kleijne et al. (2002). N.B. As well as describing new species Kleijne et al (2002) significantly revised the taxonomic concepts of A. unicornis and A. spatula. Essentially A. unicornis sensu Jordan & Chamberlain (1993) corresponds to A. gaudii whilst A. spatula sensu Jordan & Chamberlain (1993) corresponds to A. unicornis sensu Kleijne et al. (2002). The confusion stems from the fact that Okada & McIntyre (1977) illustrated two rather different specimens as A. unicornis, See Kleijne et al. (2002) for detailed synonymies.

Distinguishing features: Coccoliths placolith-like, with asymmetrical distal flange

Farinacci & Howe catalog pages: Alisphaera + + *


Morphology remarks: Coccosphere monothecate, ellipsoidal with apical opening. Coccoliths arranged on coccosphere with long axis aligned equatorially and broader flange directed toward apical opening.
Coccoliths placolith-like, with asymmetrical distal flange, one side broader with a variable extension, other side narrow and in many species with 8-10 teeth projecting into central area. Plate in central area formed by extension of tube elements inward, usually with irregular central fissure. No discrete circumflagellar coccoliths.

Biology & life-cycles: Combination cells of Polycrater sp. and Alisphaera gaudii have been observed (Cros et al. 2000, Cros & Fortuño 2002), and of P. galapagensis with A. unicornis (Supraha et al. 2018)

Search data:
TagsLITHS: placolith, asymmetric, elliptical, RIM: spine(s),
CSPH: oblate (broad), ovoid, spherical, monomorphic, V-UNITS: distal shield, R-UNITS: prox shield, px-plate, DETAILS: ca_conjunct,
MetricsLith size: 1->3µm; Coccosphere size: 4.5->16µm;
Sources:
The morphological data given here can be used on the advanced search page. See also these notes

See also: Polycrater ;

Geological Range:
Notes: Only occasional specimens observed and these are probably best referred to as Alisphaera sp.
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): at base of Gelasian Stage (0% up, 2.6Ma, in Gelasian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Cros, L. & Fortuño, J. -M. (2002). Atlas of northwestern Mediterranean coccolithophores. Scientia Marina. 66: 186-. gs

Cros, L., Kleijne, A. & Young, J. R. (2000a). Coccolithophorid diversity in the genus Polycrater and possible relationships with other genera. Journal of Nannoplankton Research. 22(2): 92-. gs

Heimdal, B. R. (1973). Two new taxa of Recent coccolithophorids. “Meteor” Forschungsergebnisse. Reihe D, Biologie. 70-75. 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

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, Special Issue. 1: 1-132. gs


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Alisphaera compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 22-10-2019

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=26 Go to Archive.is to create a permanent copy of this page - citation notes



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