Conusphaera


Classification: Mesozoic -> Nannoliths inc sedis -> Eoconusphaeraceae -> Conusphaera
Sister taxa: Conusphaera, Eoconusphaera,

Distinguishing features: Tapering nannoliths with steeply sloping rim and central area filled with a core of radially arranged elements. Most commonly seen in side view. The rim elements are joined along vertical sutures (protolith-rim-like).


Daughter taxa: (blue => in age window 0-800Ma) Granddaughter taxa
Tapering nannoliths with steeply sloping rim and central area filled with a core of radially arranged elements, which in LM shows relatively uniform birefringence with an axial extinction line. Most commonly seen in side view.

Like C. mexicana but LM image shows spiralling pattern across the core, and curving extinction lines.

small, elliptical species
Small Conusphaera (<4 µm) with central core divided into 4 segments in side view. Elliptical in plan view

A species of Conusphaera lacking a spinewith an elliptical outline, low rim, and central area spanned by a plate formed from radial elements.

Specimens not identified to species level

Taxonomy:

Citation: Conusphaera Trejo, 1969
Rank: Genus
Type species: Conusphaera mexicana Trejo, 1969
Synonyms: Cretaturbella Thierstein 1971

Farinacci & Howe catalog pages: Conusphaera * , Cretaturbella *

Distinguishing features: Tapering nannoliths with steeply sloping rim and central area filled with a core of radially arranged elements. Most commonly seen in side view. The rim elements are joined along vertical sutures (protolith-rim-like).

Geological Range:
Last occurrence (top): in lower part of Aptian Stage (25% up, 123Ma, in Aptian stage). Data source: Total of range of species in this database
First occurrence (base): in mid part of Kimmeridgian Stage (49% up, 154.7Ma, in Kimmeridgian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Bown, P. R. & Cooper, M. K. E. (1998). Jurassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 34-85. gs

Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Early Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 86-131. gs

Trejo, M. (1969). Conusphaera mexicana, un nuevo coccolitoforido del Jurassico Superior de Mexico. Revista del Instituto Mexicano del Petroleo. 1: 5-15. gs


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Conusphaera compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 17-10-2019

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10269 Go to Archive.is to create a permanent copy of this page - citation notes



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