Cruciellipsis


Classification: Mesozoic -> Podorhabdales -> Cretarhabdaceae -> Cruciellipsis
Sister taxa: Cretarhabdus, Cruciellipsis, Flabellites, Grantarhabdus, Helenea, Mattiolia, Miravetesina, Pickelhaube, Retecapsa, Speetonia,

Distinguishing features: Cretarhabdids with relatively broad shields; central area spanned by a broad axial cross, with strong medial extinction lines.


Daughter taxa: (blue => in age window 0-800Ma) Granddaughter taxa
Cretarhabdids with relatively broad shields and a central area spanned by tapering, broad, axial cross bars that are strongly birefringent with median extinction lines.

Specimens not identified to species level

Taxonomy:

Citation: Cruciellipsis Thierstein, 1971
Rank: Genus
Type species: Cruciellipsis cuvillieri (Manivit, 1966) Thierstein, 1971 emend. Wind and Cepek, 1979

Farinacci & Howe catalog pages: Cruciellipsis + *

Distinguishing features: Cretarhabdids with relatively broad shields; central area spanned by a broad axial cross, with strong medial extinction lines.


Morphology remarks: Cross bright when aligned with polariser, dark at 45° position, with gypsum plate cross shows opposite colours to adjacent rim  

Geological Range:
Last occurrence (top): at top of Hauterivian Stage (100% up, 130.8Ma, in Hauterivian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Berriasian Stage (0% up, 145Ma, in Berriasian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

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

Thierstein, H. R. (1971). Tentative Lower Cretaceous Calcareous Nannoplankton Zonation. Eclogae Geologicae Helvetiae. 64: 459-488. gs

Wind, F. H. & Cepek, P. (1979). Lower Cretaceous calcareous nannoplankton from DSDP Hole 397A (northwest African Margin). Initial Reports of the Deep Sea Drilling Project. 47A: 221-235. gs


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Cruciellipsis 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=10327 Go to Archive.is to create a permanent copy of this page - citation notes



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