Rhomboasteraceae


Ancestry: Coccolithophores -> Nannolith families inc sed -> Rhomboasteraceae
Sister taxa: Braarudosphaeraceae, Ceratolithaceae, Lapideacassaceae, Lithostromationaceae, Nannolith genera inc sed, Rhomboasteraceae,

Short diagnosis: Nannoliths with rhombic and tri-radiate morphologies, and non-birefringent images in XPL. Incorporating the genera Rhomboaster and Tribrachiatus.


Daughter taxa (blue => in age window 0-300Ma) Granddaughter taxa
Solid nannoliths that include rhombic, rhombic with spinose extensions and forms composed of two superimposed tri-radiate cycles.

Solid nannoliths with three rays that typically have terminal bifurcations.

Taxonomy:

Citation: Rhomboasteraceae Bown, 2005
Rank: Family
Notes & discussion: Rhomboaster and Tribrachiatus nannoliths comprise an evolutionary lineage from the oldest, rhombic nannoliths (cuspis-type), through intermediate forms with two superimposed tri-radiate cycles (bramlettei-type), to the youngest, single cycle tri-radiate forms (orthostylus-type). Bybell & Self-Trail (1995, 1997) argued for the use of one genus only, whereas others have retained both (e.g. Aubry, 1996). Both genera are included here: Rhomboaster for nannoliths with three-dimensional, rhombic to bicyclic tri-radiate morphologies, and Tribrachiatus for flatter morphologies with a single tri-radiate cycle.

Farinacci & Howe catalog pages:

Short diagnosis: Nannoliths with rhombic and tri-radiate morphologies, and non-birefringent images in XPL. Incorporating the genera Rhomboaster and Tribrachiatus.

Geological Range:
Last occurrence (top): within Ypresian Stage (47.84-55.96Ma, top in Ypresian stage). Data source: Total of range of species in this database
First occurrence (base): within Ypresian Stage (47.84-55.96Ma, base in Ypresian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Aubry, M.-P., (1996). Towards an Upper Paleocene-Lower Eocene high resolution stratigraphy based on calcarous nannofossil stratigraphy. Israel Journal of Earth-Sciences, 44(239-253).

Bown, P.R., (2005). Palaeogene calcareous nannofossils from the Kilwa and Lindi areas of coastal Tanzania (Tanzania Drilling Project 2003-4). Journal of Nannoplankton Research, 27(1): 21-95.

Bybell, L.M. & Self-Trail, J., (1995). Evolutionary, biostratigraphic and taxonomic study of calcareous nanofossils from a continuous Palaeocene-Eocene boundary section in New Jersey. United States Geological Survey professional paper, 1554: 1-36.

Bybell, L. & Self-Trail, J., (1997). Late Paleocene and Early Eocene calcareous nannofossils from three boreholes in an onshore-offshore transect from New Jersey to the Atlantic continental rise. Proceedings of the Ocean Drilling Program. Scientific Results, 150: 91-110.


Nannotax3 - Coccolithophores - Rhomboasteraceae by: Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 24-3-2017

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