Helicosphaeraceae


Classification: Coccolithophores -> Zygodiscales -> Helicosphaeraceae
Sister taxa: Helicosphaeraceae, Pontosphaeraceae, Zygodiscaceae,

Daughter taxa: (blue => in age window 0-800Ma) Granddaughter taxa
Coccoliths with helical flange; arranged spirally on the coccosphere

Taxonomy:

Citation: Helicosphaeraceae Black, 1971
Rank: Family
Notes & discussion: Taxa included: family contains only one genus, Helicosphaera

Distinguishing features: Varimorphic; liths placolith-like but with helical shield structure; arranged in spiral on coccosphere

Farinacci & Howe catalog pages: Helicosphaeraceae [no catalog entry yet], ,


Morphology remarks: Coccospheres ellipsoidal with a prominent flagellar opening. Coccoliths arranged spirally round the coccosphere and may vary slightly in size and shape from the antapex to the flagellar pole.
Coccolith structure - Outer rim (V-units) of the coccoliths are modified into a helical flange, ending in a wing or spike. R-units form the baseplate and extend to form blanket of small elements (Young et al. 2004). Central-area bars may be conjunct, disjunct or absent. Theodoridis (1984) discusses the structure.

Search data:
TagsLITHS: placolith, RIM: wing,
CSPH: ellipsoidal, varimorphic, V-UNITS: distal shield, R-UNITS: blanket, c-str, px-plate, DETAILS: rim-bicyclic, isogyres kinked, isogyres oblique, isogyres separated,
MetricsLith size: 4->22┬Ám;
Sources:
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: Total of range of species in this database
First occurrence (base): in lower part of Ypresian Stage (28% up, 53.7Ma, in Ypresian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Black, M. (1971c). The systematics of coccoliths in relation to the paleontological record. In, Funnell, B. M. & Riedel, W. R. (eds) The Micropaleontology of the Oceans. Cambridge University Press, Cambridge 611-624. gs

Perch-Nielsen, K. (1985a). Cenozoic calcareous nannofossils. In, Bolli, H. M. , Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge 427-555. gs

Theodoridis, S. (1984). Calcareous nannofossil biostratigraphy of the Miocene and revision of the helicoliths and discoasters. Utrecht Micropaleontological Bulletin. 32: 1-271. gs

Young, J. R., Henriksen, K. & Probert, I. (2004b). Structure and morphogenesis of the coccoliths of the CODENET species. In, Thierstein, H. R. & Young, J. R. (eds) Coccolithophores - From molecular processes to global impact. Springer, Berlin 191-216. gs


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Helicosphaeraceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 21-7-2019

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=696 Go to Archive.is to create a permanent copy of this page - citation notes



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