Nannotax3 - ntax_mesozoic - Conusphaera

Conusphaera


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

Distinguishing features:
Parent taxon (Eoconusphaeraceae): Nannoliths with a truncated-cone-like morphology constructed from an outer rim of thin, elements joined along vertical sutures, and an inner core of numerous radial lamellae that may protrude distally.
This taxon: 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 (time control age-window is: 0-800Ma)Granddaughter taxa
Conusphaera mexicana
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.
C. mexicana subsp. mexicana
C. mexicana subsp. minor

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

small, elliptical species
Conusphaera maledicto
Small Conusphaera (<4 µm) with central core divided into 4 segments in side view. Elliptical in plan view. H/W < 1.

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

Conusphaera sp.
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:
Parent taxon (Eoconusphaeraceae): Nannoliths with a truncated-cone-like morphology constructed from an outer rim of thin, elements joined along vertical sutures, and an inner core of numerous radial lamellae that may protrude distally.
This taxon: 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).


Morphology: THe iner core consists of steeply-inclined, radially arranged, lath-like elements, with anti-clockwie imbrication.  

Search data:
TagsLITHS: nannolith-radiate, elliptical, cylindrical, CA: closed, CROSS-POLARS: rim-unicyclic,
MetricsLith size: 3->9µm;
Data source notes: size range of included species
The morphological data given here can be used on the advanced search page. See also these notes

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: 9-12-2021

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Short stable page link: https://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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