Haqius


Classification: Mesozoic -> Heterococcoliths inc sedis -> placoliths inc sedis -> Haqius
Sister taxa: Ellipsolithus, Haqius, Markalius, Mattiolia, Repagulum,

Distinguishing features: Unicyclic, elliptical and circular placolith coccoliths with a narrow or closed central area and a characteristically dark gray (low birefringence) XPL image.


Daughter taxa: (blue => in age window 0-800Ma)
Large (8-10 µm) circular Haqius species.
Large (7-15µm) elliptical Haquis species
Small to medium (3-7 µm) elliptical Haquis species 
Specimens not identified to species level

Taxonomy:

Citation: Haqius Roth, 1978
Rank: Genus
Type species: Coccolithites circumradiatus Stover, 1966 designated by Roth (1978).
Synonyms: Esgia Worsley 1971

Farinacci & Howe catalog pages: Haqius *

Distinguishing features: Unicyclic, elliptical and circular placolith coccoliths with a narrow or closed central area and a characteristically dark gray (low birefringence) XPL image.


Morphology remarks: Worsley (1971) described the genus Esgia based on a specimen similar to Haqius circumradiatus. We use Haqius here as it alone has consistently been used for coccoliths of this group.

Search data:
TagsLITHS: placolith, circular, elliptical, CROSS-POLARS: rim-unicyclic, V-prominent,
MetricsLith size: 3->10µm;
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): in upper part of Campanian Stage (67% up, 75.9Ma, in Campanian stage). Data source: Total of range of species in this database
First occurrence (base): in upper part of Tithonian Stage (62% up, 147.7Ma, in Tithonian 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

Roth, P. H. (1978). Cretaceous nannoplankton biostratigraphy and oceanography of the northwestern Atlantic Ocean. Initial Reports of the Deep Sea Drilling Project. 44: 731-760. gs V O

Stover, L. E. (1966). Cretaceous coccoliths and associated nannofossils from France and the Netherlands. Micropaleontology. 12(2): 133-167. gs

Worsley, T. R. (1971). Calcareous nannofossil zonation of Upper Jurassic and Lower Cretaceous sediments from the Western Atlantic. In, Farinacci, A. (ed.) Proceedings of the Second Planktonic Conference Roma 1970. Edizioni Tecnoscienza, Rome 2: 1301-1321. gs


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Haqius compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 29-9-2020

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10490 Go to Archive.is to create a permanent copy of this page - citation notes



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