Sphenolithus apoxis Conical sphenolith with a compound apical spine. (like S. abies but older)
Sphenolithus moriformis Beehive shaped sphenolith, apical elements not in extinction in vertical position. No spine, upper and lower parts of similar size.
Large species
Sphenolithus grandis Large (>10 µm) beehive shaped sphenoliths (Mid-Late Miocene)
Sphenolithus puniceus Hemispherical, like S. moriformis but larger (7-11 µm) and therefore more birefringent (Oligocene - Early miocene)
Sphenolithus acervus Large (>8.0µm) globular, coarsely-constructed sphenolith without a spine. (Palaeocene - Early Eocene)
Citation: Sphenolithus moriformis groupRank: species groupSynonyms:
S. primus group sensu Howe 2021
Taxonomic discussion: This group was recognised, with broadly the same content, by Bown & Dunkley Jones 2006, Bergen et al. 2017 and Howe 2021. Howe (2021) changed the name to S. primus group, since this is the ancestral species. We retain the established name here, since we prefer to name groups after abundant and universally accepted, species.
Species in this group are mostly poorly defined and of limited biostratigraphic value. Many workers only S. moriformis &/or S. abies.
Distinguishing features: Parent taxon (Sphenolithus): Conical nannoliths with a concave base, consisting of a mass of elements radiating from a common origin. This taxon: Conical and hemispherical sphenoliths without prominent apical spines.
Farinacci & Howe catalog pages:
Morphology:
Howe 2021 f1 01.JPG
Howe 2021 f1 03.JPG
Size: Search data:
:
Lith size: 3->12µm;
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:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Neptune data: this is a higher taxon page so Neptune data is not plotted. For the customisable plot option go to a genus page Parent: Sphenolithus
References:
Bergen, J. A., de Kaenel, E., Blair, S. A., Boesiger, T. M. & Browning, E. (2017). Oligocene-Pliocene taxonomy and stratigraphy of the genus Sphenolithus in the circum North Atlantic Basin: Gulf of Mexico and ODP Leg 154. Journal of Nannoplankton Research. 37(2-3): 77-112. gsO
Bown, P. R. & Dunkley Jones, T. (2006). New Paleogene calcareous nannofossil taxa from coastal Tanzania: Tanzania Drilling Project Sites 11 to 14. Journal of Nannoplankton Research. 28(1): 17-34. gsVO
Howe, R. (2021). Ultrastructure and taxonomy of the family Sphenolithaceae. Journal of Nannoplankton Research. 39(1): 29-75. gsO
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
S. moriformis group compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 30-9-2022
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