Semihololithus


Classification: Coccolithophores -> Holococcoliths -> fossil holococcoliths -> Semihololithus
Sister taxa: Clathrolithus, Corannulus, Daktylethra, Holodiscolithus, Lanternithus, Multipartis, Octolithus, Orthozygus, Quadrilateris, Semihololithus, Varolia, Youngilithus, Zygrhablithus, f. holococcoliths unid.,

Daughter taxa: (blue => in age window 0-800Ma)
Cavate holococcoliths comprising a thick proximal plate and a solid domed distal surface with perforations or pits.
Small holococcolith seen in side view comprising a thin proximal plate and a thin-walled tapering distal process that surrounds a central cavity divided in half by a narrow wall.
Small to medium sized cavate holococcolith seen in side view comprising a thin proximal plate, thick walls and a thin-walled, hollow distal process/spine that tapers initially then becomes parallel sided.
Large, blocky, with steep-walled rim and domed upper surface. Only known from LM side view
Similar to Semihololithus biskayae but smaller and with a thinner proximal plate and relatively larger central cavity.
Medium-sized holococcolith seen in side view comprising a thin proximal plate, thick walls and a relatively thick-walled rapidly tapering cavate distal process/spine.
Broadly elliptical coccolith with low tube and high distal cover with four very large openings
Small elliptical holococcolith with domal cover with single cycle of ca 7 large pores
Specimens which cannot be assigned to any established species

Taxonomy:

Citation: Semihololithus Perch-Nielsen, 1971
Rank: Genus
Type species: Semihololithus biskayae Perch-Nielsen, 1971

Distinguishing features: Paleogene holococcoliths usually seen in side view and comprising a thick proximal plate and spine or process, typically with a cavity or axial canal.

Farinacci & Howe catalog pages: Semihololithus *

Search data:
Tags
MetricsLith size: 3->7┬Ám;
Sources:
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): at top of Priabonian Stage (100% up, 33.9Ma, in Priabonian stage). Data source: Total of range of species in this database
First occurrence (base): near top of Selandian Stage (87% up, 59.5Ma, in Selandian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Perch-Nielsen, K. (1971). Einige neue Coccolithen aus dem Paläozän der Bucht von Biskaya und dem Eozän der Labrador See. Bulletin of the Geological Society of Denmark. 21: 347-361. gs :: ::


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Semihololithus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 2-7-2020

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=1241 Go to Archive.is to create a permanent copy of this page - citation notes



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