S. moriformis group


Classification: Coccolithophores -> Discoasterales -> Sphenolithaceae -> Sphenolithus -> S. moriformis group
Sister taxa: S. capricornutus group, S. dissimilis group, S. moriformis group, S. heteromorphus group, S. predistentus group, S. furcatolithoides group, S. radians group, S. conspicuus group, S. sp.,

Daughter taxa: (blue => in age window 0-800Ma)
Moderately elevated sphenolith with cuspate outline and with extinction line going down long axis of spine.
Conical sphenolith with a compound apical spine. (like S. abies but older)
Hemispherical with a flared proximal cycle and arcuate proximal surface
Like S. abies/moriformis but smaller, <4µm & base broad
Beehive shaped sphenolith, apical elements not in extinction in vertical position. No spine, upper and lower parts of similar size.
Hemispherical, like S. moriformis but larger (7-11 µm) and therefore more birefringent
Large (>10 µm) beehive shaped sphenoliths
Eocene species
Large (>8.0µm) globular, coarsely-constructed sphenolith without a spine.
Small with dome-shaped opening on proximal side

Taxonomy:

Citation: Sphenolithus moriformis group
Rank: species group
Notes & discussion: Species in this group are mostly poorly defined and of limited biostratigraphic value. Many workers only S. moriformis &/or S. abies.

Distinguishing features: Conical and hemispherical sphenoliths without prominent apical spines.

Farinacci & Howe catalog pages:

Search data:
TagsLITHS: nannolith-radiate, N: 3D-radiate, conical, circular, RIM: tiered,
CSPH: not known, DETAILS: isogyres radial,
MetricsLith size: 3->12µm;
Sources:
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): near base of Piacenzian Stage (14% up, 3.5Ma, in Piacenzian stage). Data source: Total of range of species in this database
First occurrence (base): near top of Danian Stage (90% up, 62.1Ma, in Danian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Perch-Nielsen, K. (1985a). Cenozoic calcareous nannofossils. In, Bolli, H. M. , Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge 427-555. gs


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S. moriformis group compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-11-2019

Taxon Search:
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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=1215 Go to Archive.is to create a permanent copy of this page - citation notes



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