fossil holococcoliths


Ancestry: Coccolithophores -> Holococcoliths -> fossil holococcoliths
Sister taxa: tubeless, convex, bridged, flat-topped, septate, open-tube, fossil holococcoliths,

Short diagnosis: Holococcolith genera only known from the fossil record


Daughter taxa (blue => in age window 0-300Ma) Granddaughter taxa
Unusual holococcoliths with non-coccolith morphology typically comprising an elliptical, concavo-convex, domed, perforate framework.

Discoidal holococcoliths with large central openings and marginal perforations or indentations; non-birefringent in plan view.

Domed cavate holococcoliths with surficial shallow pits.

Elliptical non-birefringent holococcoliths with perforations.

Cavate holoccoliths with distinct crystallographic blocks.

Holococcoliths with multiple elements in the central area

Holoccoliths with distinct rim and cover blocks, typically eight.

Holococcoliths that typically have a spine or process and transverse bridge or bars.

Rectangular holococcoliths formed from four thin blocks that are birefringent in XPL.

Paleogene holococcoliths usually seen in side view and comprising a thick proximal plate and spine or process, typically with a cavity or axial canal.

Cavate, thin walled, box-like holococcoliths usually seen in side view.

Geometrically shaped non-birefringent holococcoliths typically possessing lateral rim spines and central area bars.

Spinose holococcoliths, which are birefringent in side view. In plan view the coccoliths are non-birefringent with a distinct figure-of-eight shaped central structure.



Taxonomy:

Citation: fossil holococcoliths
Rank: informal group
Synonyms: Calyptrosphaeraceae Boudreaux & Hay, in Hay et al 1967

Farinacci & Howe catalog pages:

Short diagnosis: Holococcolith genera only known from the fossil record


Morphology remarks: Whilst this is a very disparate group of genera they are mostly larger than extant holococcoliths and tend to have distnctive shapes, rather than being simple discs.

Geological Range:
Last occurrence (top): within Ionian Stage (0.13-0.78Ma, top in Ionian stage). Data source: Total of range of species in this database
First occurrence (base): within Campanian Stage (72.05-83.64Ma, base in Campanian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Hay, W.W.; Mohler, H.P.; Roth, P.H.; Schmidt, R.R. & Boudreaux, J.E., (1967). Calcareous nannoplankton zonation of the Cenozoic of the Gulf Coast and Caribbean-Antillean area, and transoceanic correlation. Transactions of the Gulf Coast Association of Geological Societies, 17: 428-480.


Nannotax3 - Coccolithophores - fossil holococcoliths by: Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 26-5-2017

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