Sphenolithus heteromorphus

Ancestry: Coccolithophores -> Discoasterales -> Sphenolithaceae -> Sphenolithus -> S. heteromorphus group -> Sphenolithus heteromorphus
Sister taxa: S. belemnos, S. calyculus, S. delphix, S. disbelemnos, S. milanetti, S. pospichalii, S. pseudoheteromorphus, S. heteromorphus,

Short diagnosis: Apical spine very well-developed. Lateral elements nearly as large as proximal elements.


Citation: Sphenolithus heteromorphus Deflandre 1953
Rank: Species
Notes & discussion: S. heteromorphus has a well developed quadrate base, in which the the upper part is nearly as large as the proximal part, which distinguishes it clearly from S. belemnos. Also the spine typically has a rather bulbous base in contrast to the straight-sided S. belemnos.

Farinacci & Howe catalog pages: Sphenolithus heteromorphus *

Short diagnosis: Apical spine very well-developed. Lateral elements nearly as large as proximal elements.

Size: Length 5-15 microns, varies considerably in all populations, possibly in part due to diagenetic overgrowth. Width usually c. 3-5 microns.

Geological Range:
Notes: Prone to reworking
Last occurrence (top): at top of NN5 zone (100% up, 13.5Ma, in Serravallian stage). Data source: zonal marker (see e.g. Young 1998)
First occurrence (base): at base of NN4 zone (0% up, 18Ma, in Burdigalian stage). Data source: FAD is very close to NN4 base , se e.g. Young (1998)

Plot of occurrence data:


Deflandre, G., (1953). Hétérogénéité intrinsèque et pluralité des éleménts dans les coccolithes actuels et fossiles. Comptes Rendus (Hebdomadaires des Séances) de l'Académie des Sciences Paris, 237: 1785-1787.

Fornaciari, E. & Agnini, C., (2009). Taxonomic note: Sphenolithus pseudoheteromorphus, a new Miocene calcareous nannofossil species from the equatorial Indian Ocean. Journal of Nannoplankton Research, 30(2): 97-101.

Young, J.R., (1998). Neogene. In: Bown, P.R. (Editor), Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publications Series. Chapman & Hall, London, pp. 225-265.

Nannotax3 - Coccolithophores - Sphenolithus heteromorphus by: Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 28-4-2017

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Comments (1)

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Bryan C. Ladner
Just wanted to point out that the correct spelling of S. heteromorphus is as indicated just now. There is no 'os' after morph, it is simply heteromorphus. I have a PDF copy of the original description by Deflandre (1953) if you need it to confirm my comment. Thanks, Bryan Ladner
Jeremy Young (NHM, UK)

Thanks Brian
You are quite right of course, this is something of a blind spot of mine. Anyway I have corrected it now (a moderately arkward process but easier than doing it in a non-database system).

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