Classification: ntax_cenozoic -> Holococcoliths -> fossil holococcoliths -> Orthozygus
Sister taxa: Clathrolithus, Corannulus, Daktylethra, Holodiscolithus, Lanternithus, Multipartis, Octolithus, Orthozygus, Quadrilateris, Semihololithus, Varolia, Youngilithus, Zygrhablithus, Unidentified fossil holococcoliths

Daughter taxa (time control age-window is: 0-800Ma)
Orthozygus arcus
Low basal coccolith with a low arched bridge; both coccolith and process are weakly-birefringent.
Orthozygus aureus
Elliptical non-birefringent holococcolith comprising a narrow rim spanned by an arched, perforate bridge. The bridge is broad and pierced by a large central hole and has a distal covering that is finely perforate. Distinguishable in both plan and side views.
Orthozygus brytika
Small, narrowly-ellliptical non-birefringent holococcolith comprising a narrow rim spanned by diagonal cross-bars.
Orthozygus occultus
Medium sized, irregularly elliptical to polygonal holococcoliths, which are dark in XPL but have distinctly high relief in phase contrast. Central hole seen in LM is a perforate cover on the distal side.
Orthozygus sudis
Holococcolith that in side-view comprises a low basal coccolith and a relatively tall, hollow spine that tapers to a point. Both coccolith and spine are birefringent and crystallographically continuous in XPL.
Orthozygus suggrandis
A large, coarsely constructed, elliptical holococcolith with a central area spanned by a transverse, bridge-like structure that broadens at each end. The rim and bridge are crystallographically disjunct.
Orthozygus sp.
Specimens which cannot be assigned to any established species


Citation: Orthozygus Bramlette & Wilcoxon, 1967
Rank: Genus
Type species: Orthozygus aureus (Stradner, 1962) Bramlette & Wilcoxon, 1967 [Zygolithus]

Distinguishing features: Holococcoliths that typically have a spine or process and transverse bridge or bars.

Farinacci & Howe catalog pages: Orthozygus *

Search data:
TagsLITHS: holococcolith, elliptical, CROSS-POLARS: V-prominent,
MetricsLith size: 3->8µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): in upper part of Rupelian Stage (74% up, 29.6Ma, in Rupelian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Lutetian Stage (23% up, 46.3Ma, in Lutetian stage). Data source: Total of range of species in this database

Plot of occurrence data:


Bramlette, M. N. & Wilcoxon, J. A. (1967b). Middle Tertiary calcareous nannoplankton of the Cipero section, Trinidad, W.I. Tulane Studies in Geology and Paleontology. 5: 93-131. gs V O


Orthozygus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-6-2021

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=976 Go to Archive.is to create a permanent copy of this page - citation notes

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