Sphenolithus milanetti


Classification: Coccolithophores -> Discoasterales -> Sphenolithaceae -> Sphenolithus -> S. heteromorphus group -> Sphenolithus milanetti
Sister taxa: S. heteromorphus, S. milanetti, S. preasii, S. belemnos, S. pseudoheteromorphus, S. conicus, S. calyculus, S. delphix, S. microdelphix, S. spinula,

Taxonomy:

Citation: Sphenolithus milanetti Maiorano & Monechi 1998
Rank: Species
Synonyms:
Notes & discussion: As discussed by Bergen et al. (2017) S pospichalii is clearly a junior synonym of S. milanetti. The holotype of Maiarano & Monechi 1998 is unfortnately a rather overgrown specimen but the  SEM image and cited specimens make it clear they are describing the same species.

Distinguishing features: Large; proximal shield wide and high; apical spine slightly extended & made up of a single crystal unit

Farinacci & Howe catalog pages: Sphenolithus milanetti *


Morphology remarks: In cross-polarized light, in the 0° position, the bright, large and high proximal shield, is prominent. The lower quadrants are larger then the upper ones and about twice the height of the latter. In the 0° position the apical spine, made up of a single unit, is extinct; in the 45° position it is bright. Short lateral elements can be seen at the base of the apical spine.

Size: 6-10µm

See also: Sphenolithus avis - similar shape but with duocrystalline spine;

Search data:
TagsLITHS: nannolith-radiate, N: 3D-radiate, conical, circular, cylindrical, RIM: tiered, CA: process, PROCESS: length-fast, monocrystalline, spine,
CSPH: not known, V-UNITS: spine, V-prominent, R-UNITS: lower-tier, middle-tier, R-prominent, DETAILS: isogyres radial,
MetricsLith size: 6->12µm;
Sources: lith height from OD and illustrated specs
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NN4 zone (14.91-17.95Ma, top in Langhian stage). Data source: Maiorano & Monechi 1998
First occurrence (base): within NN4 zone (14.91-17.95Ma, base in Burdigalian stage). Data source: Maiorano & Monechi 1998

Plot of occurrence data:

  • Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
  • Note to users in China - the diagram may not plot unless you use a VPN since I use google services on the website. If this is a problem please contact me 谢谢.
  • Taxon plotted: Sphenolithus milanetti, synonyms included - Sphenolithus milanettii; Sphenolithus milanetti;
  • space-time plot :: Samples map :: Parent: S. heteromorphus group

    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. gs :: view :: open

    Fornaciari, E., Raffi, I., Rio, D., Villa, G., Backman, J. & Olafsson, G. (1990). Quantitative distribution patterns of Oligocene and Miocene calcareous nannofossils from the western equatorial Indian Ocean. Proceedings of the Ocean Drilling Program, Scientific Results. 115: 237-254. gs :: view :: open

    Jiang, S., Wang, Y., Varol, O., da Gama, R. O. B. P. & Blaj, T. (2016). A new early Miocene Sphenolithus species from the South China Sea. Journal of Nannoplankton Research. 36(1): 61-63. gs :: view :: open

    Maiorano, P. & Monechi, S. (1998). Revised correlations of early and middle Miocene calcareous nannofossil events and magnetostratigraphy from DSDP Site 563 (North Atlantic Ocean). Marine Micropaleontology. 35(235-255): -. gs :: ::

    Olafsson, G. (1989). Quantitative calcareous nannofossil biostratigraphy of upper Oligocene to middle Miocene sediment from ODP Hole 667A and middle Miocene sediment from DSDP Site 574. Proceedings of the Ocean Drilling Program, Scientific Results. 108: 9-22. gs :: view :: open


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    Sphenolithus milanetti compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-7-2020

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=1303 Go to Archive.is to create a permanent copy of this page - citation notes



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