Nannotax3 - ntax_mesozoic - Chiastozygus lamprostauros <title>Nannotax3 - ntax_mesozoic - Chiastozygus lamprostauros

Chiastozygus lamprostauros


Classification: ntax_mesozoic -> Eiffellithales -> Chiastozygaceae -> Chiastozygus -> Chiastozygus lamprostauros
Sister taxa: C. amphipons, C. bifarius, C. lamprostauros, C. litterarius, C. platyrhethus, C. spissus ⟩⟨ C. antiquus, C. garrisonii, C. stylesii, C. trabalis ⟩⟨ C. propagulis, C. quadriperforatus, C. synquadriperforatus, C. tenuis, C. sp.

Distinguishing features:
Parent taxon (Chiastozygus): Murolith (loxolith) coccoliths with relatively narrow rim and wide central area spanned by diagonal bars. Inner/proximal rim cycle is variably developed and so the LM image may be unicyclic or bicyclic.
This taxon: Small to medium-sized (4.3–7.2 μm) normally elliptical, with a narrow (~1.2 μm) rim; central area relatively wide; cross is brighter than the rim when the long axis is at 45°


Taxonomy:

Citation: Chiastozygus lamprostauros Aguado, in Aguado et al. 2022
Rank: species

Farinacci & Howe catalog pages: C. lamprostauros *

Distinguishing features:
Parent taxon (Chiastozygus): Murolith (loxolith) coccoliths with relatively narrow rim and wide central area spanned by diagonal bars. Inner/proximal rim cycle is variably developed and so the LM image may be unicyclic or bicyclic.
This taxon: Small to medium-sized (4.3–7.2 μm) normally elliptical, with a narrow (~1.2 μm) rim; central area relatively wide; cross is brighter than the rim when the long axis is at 45°


Morphology:

This species has an axial ratio ~ 1.4 and a relatively narrow rim, which is dark and diffusely bicyclic under XPL. The diag- onal cross spanning the central area have narrow (~0.5 μm) arms that show median lines and remain dark when the longitudinal direction is oriented at 0◦. These arms are seen simple (without median lines) and bright under XPL when the longitudinal direction is oriented at 45◦. The angle between the arms of the cross is greater (~105◦) in the longitudinal direction than in the transverse direction (~75◦). The arms of the diagonal cross are asymmetrical (slightly rotated) with respect to the axes of the ellipse. In some specimens, the diagonal cross supports the base of a distal stem. [Aguado et al. 2022]

Size:


Ecology & Biogeography


Biology & life-cycles

Phylogenetic relations

Search data:
LITHS: murolith, elliptical, CA: cross-axial, CROSS-POLARS: rim-bicyclic,
Lith size: 4.3->7.2µm;
Data source notes: Aguado et al. 2022
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: "Probably most of the late Barremian–early Aptian C. litterarius specimens from the literature should be assigned to C. lamprostauros." [Aguado etal. 2022]
Last occurrence (top): within NC7a subzone (122.25-123.88Ma, top in Aptian stage). Data source: Aguado et al. 2022
First occurrence (base): within NC5e subzone (126.40-127.31Ma, base in Barremian stage). Data source: Aguado et al. 2022

Plot of occurrence data:

References:

Aguado, R., Company, M., O'Dogherty, L., Sandoval, J. & Martinez, M. (2022). New insights into the Barremian–lower Aptian calcareous nannofossils of the Mediterranean Tethys: Chronostratigraphic and paleobiogeographic implications. Marine Micropaleontology. 173: 1-24. gs V O

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Chiastozygus lamprostauros compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 30-1-2023

Taxon Search:
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