Orthozygus arcus


Classification: ntax_cenozoic -> Holococcoliths -> fossil holococcoliths -> Orthozygus -> Orthozygus arcus
Sister taxa: O. arcus, O. aureus, O. brytika, O. occultus, O. sudis, O. suggrandis, O. sp.

Taxonomy:

Citation: Orthozygus arcusDunkley Jones, Bown & Pearson, 2009
Rank: Species
Taxonomic discussion: Usually seen in oblique view. The spine is broader and lower than that of Orthozygus aureus and does not have distinct perforations. Crystallographic properties similar to those of O. sudis but with a low and smoothly arching bridge instead of a pointed spine. Differentiated from O. occultus by its visible birefringence in XPL and distinct low arched bridge.

Distinguishing features: Low basal coccolith with a low arched bridge; both coccolith and process are weakly-birefringent.

Farinacci & Howe catalog pages: O. arcus *

Search data:
TagsLITHS: holococcolith, elliptical, hollow, CA: process, closed, CROSS-POLARS: V-prominent,
MetricsLith size: 4->5┬Ám;
Data source notes: lith size from OD & extended slightly
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NP21 zone (32.92-34.44Ma, top in Rupelian stage). Data source: Dunkley Jones et al., 2009
First occurrence (base): within NP19-20 zone (34.44-36.97Ma, base in Priabonian stage). Data source: Dunkley Jones et al., 2009

Plot of occurrence data:

References:

Dunkley Jones, T., Bown, P. R. & Pearson, P. (2009). Exceptionally well preserved upper Eocene to lower Oligocene calcareous nannofossils (Prymnesiophycidae) from the Pande Formation (Kilwa Group), Tanzania. Journal of Systematic Palaeontology. 7(4): 359-411. gs


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Orthozygus arcus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 24-2-2021

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=977 Go to Archive.is to create a permanent copy of this page - citation notes



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