Discoasteraceae


Ancestry: Coccolithophores -> Discoasterales -> Discoasteraceae
Sister taxa: Discoasteraceae, Fasciculithaceae, Heliolithaceae, Sphenolithaceae,

Short diagnosis: Discoidal discoasteralids formed of one, non-birefringent in plan view, cycle.


Daughter taxa (blue => in age window 0-300Ma) Granddaughter taxa
Radiate nannoliths with each ray formed of a discrete crystal-unit, with the c-axes perpendicular to the nannolith surface.

Discoasterids with bifurcate ray tips that meet to form a basket like structure



Taxonomy:

Citation: Discoasteraceae Tan, 1927
Rank: Family

Farinacci & Howe catalog pages:

Short diagnosis: Discoidal discoasteralids formed of one, non-birefringent in plan view, cycle.


Morphology remarks: Discoidal nannoliths of 3-40 elements radiating from a common centre. C-axes vertical, so nannoliths appear dark in plane-polarised light.

Evolution & Phylogeny: Almost certainly evolved from the Heliolithaceae, by loss of the R-units. Disappear from the fossil record at the end of the Pliocene. There is a long term trend in ecology of the group toward reduction of number of elements and increase in space between the elements (Bukry 1971)

Geological Range:
Last occurrence (top): within Gelasian Stage (1.81-2.59Ma, top in Gelasian stage). Data source: Total of range of species in this database
First occurrence (base): within Thanetian Stage (55.96-59.24Ma, base in Thanetian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Bukry, D., (1971). Discoaster evolutionary trends. Micropaleontology, 17: 43-52.

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.

Tan, S.H., (1927). Discoasteridae incertae sedis. Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen, Sect Sci, 30: 411-419.


Nannotax3 - Coccolithophores - Discoasteraceae by: Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 28-4-2017

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