Nannotax3 - Coccolithophores - Helicosphaeraceae

Helicosphaeraceae

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

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

Daughter taxa: (blue => in age window 0-800Ma)					Granddaughter taxa
				Helicosphaera Coccoliths with helical flange; arranged spirally on the coccosphere	H. carteri group H. walbersdorfensis group H. ampliaperta group H. recta group H. lophota group H. sp.

Taxonomy:

Citation: Helicosphaeraceae Black, 1971

Rank: Family

Notes & discussion: Taxa included: family contains only one genus, Helicosphaera

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

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

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:

Tags	LITHS: 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,
Metrics	Lith size: 4->22µm; 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:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Neptune data: this is a higher taxon page so Neptune data is not plotted. For the customisable plot option go to a genus page Parent: Zygodiscales

References:

Black, M., (1971). The systematics of coccoliths in relation to the paleontological record. In: Funnell, B.M. and Riedel, W.R. (Editors), The Micropaleontology of the Oceans. Cambridge University Press, Cambridge, pp. 611-624.GS

Perch-Nielsen, K., (1985). Cenozoic calcareous nannofossils. In: Bolli, H.M., Saunders, J.B. and Perch-Nielsen, K. (Editors), Plankton Stratigraphy. Cambridge University Press, Cambridge, pp. 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., (2004). Structure and morphogenesis of the coccoliths of the CODENET species. In: Thierstein, H.R. and Young, J.R. (Editors), Coccolithophores - From molecular processes to global impact. Springer, pp. 191-216.GS

Helicosphaeraceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 25-3-2019

Taxon Search:

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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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