Nannotax3 - ntax_mesozoic - Cruciellipsis

Cruciellipsis


Classification: ntax_mesozoic -> Podorhabdales -> Cretarhabdaceae -> Cruciellipsis
Sister taxa: Mattiolia, Wisea ⟩⟨ Speetonia ⟩⟨ Cruciellipsis, Flabellites, Grantarhabdus, Helenea ⟩⟨ Cretarhabdus, Retecapsa, Pickelhaube, Miravetesina

Distinguishing features:
Parent taxon (Cretarhabdaceae): Regular placoliths; central-area spanned by elevated distal structure typically with cross bars and central spine.
The distal shield usually weakly bicyclic, with narrow outer-cycle and broad inner-cycle; elements usually radial and non-imbricate. LM image is moderately birefringent. V/R structure unclear.

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


Daughter taxa (time control age-window is: 0-800Ma)Granddaughter taxa
Cruciellipsis cuvillieri
Large (8-12 µm) Cretarhabdids with relatively broad shields and a central area spanned by tapering, broad, axial cross bars that are strongly birefringent with median extinction lines.
C. cuvillieri subsp. cuvillieri
C. cuvillieri subsp. grandis

Cruciellipsis sp.
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:
Parent taxon (Cretarhabdaceae): Regular placoliths; central-area spanned by elevated distal structure typically with cross bars and central spine.
The distal shield usually weakly bicyclic, with narrow outer-cycle and broad inner-cycle; elements usually radial and non-imbricate. LM image is moderately birefringent. V/R structure unclear.

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


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

Search data:
TagsLITHS: placolith, elliptical, CA: cross-axial, ca_disjunct, grill, process, CROSS-POLARS: rim-unicyclic, R-prominent,
MetricsLith size: 8->16µm;
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): 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 V O

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 V O


nannotaxlogo400px

Cruciellipsis compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 16-1-2022

Taxon Search:
Advanced Search

Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10327 Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet on this page. Please do add comments if you spot any problems, or have information to share

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics