Cruciellipsis


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

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


Daughter taxa (blue => in age window 0-300Ma) 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 + *

Short diagnosis: 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): within Hauterivian Stage (130.77-133.88Ma, top in Hauterivian stage). Data source: Total of range of species in this database
First occurrence (base): within Berriasian Stage (139.39-145.01Ma, base 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. (Editor), Calcareous nannofossil biostratigraphy. British Micropalaeontological Society Publication Series. Chapman & Hall, pp. 86-131.

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

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.


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Cruciellipsis compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 22-1-2018

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