Bown_2005_JNR_pl44-fig33.jpg
Bown_2005_JNR_pl44-fig34.jpg
BownandDJ2012_JNR_pl10-fig1.jpg
Bergen et al 2017 fig3 09.JPG
Bergen et al 2017 pl02 27-28.JPG
Bergen et al 2017 pl02 29-30.JPG
BownandDJ2012_JNR_pl10-fig2.jpg
Dunkley Jones et al 2009_pl14-fig5.jpg
Dunkley Jones et al 2009_pl14-fig5^.jpg
Fioroni et al 2015 pl2 f22.jpg
Muller74Leg25-pl4-2.JPG
ShamrockWatkins2012-pl9-fig7b.jpgTaxonomy:
Distinguishing features: Medium to large sphenolith with a tall compound spine. Distinguished from Sphenolithus radians by its larger size, more irregular outline and apical cycles that extend laterally beyond the base of the apical spine.
Farinacci & Howe catalog pages: Sphenolithus pseudoradians *
Morphology remarks: According to Bergen et al. 2017 "this species is easily distinguished by apparent thickening along the median axis of its apical spine."
| Tags | LITHS: nannolith-radiate, N: 3D-radiate, conical, circular, cylindrical, CA: process, PROCESS: length-fast, multicrystalline, spine, CSPH: not known, V-UNITS: V-prominent, R-UNITS: all, lower-tier, spine, middle-tier, R-prominent, DETAILS: isogyres radial, |
| Metrics | Lith size: 10->20µm; Sources: lith height from illustrated specs |
Geological Range:
Notes: The base of S. pseudoradians was used as the zonal marker for the NP19/20 boundary but the species ranges much lower so typically the zones are combined - as NP19/20 - (see Perch-Nielsen 1985).
Bergen et al. (2017) suggest a range of NP18-24
Last occurrence (top): within NP24 zone (26.84-29.62Ma, top in Chattian stage). Data source: Perch-Nielsen 1985
First occurrence (base): within NP15 zone (42.87-46.29Ma, base in Lutetian stage). Data source: Perch-Nielsen 1985
Plot of occurrence data:
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 Bown, P. R. & Dunkley Jones, T. (2012). Calcareous nannofossils from the Paleogene equatorial Pacific (IODP Expedition 320 Sites U1331-1334). Journal of Nannoplankton Research. 32(2): 3-51. gs :: view :: open Bown, P. R. (2005). Palaeogene calcareous nannofossils from the Kilwa and Lindi areas of coastal Tanzania (Tanzania Drilling Project 2003-4). Journal of Nannoplankton Research. 27(1): 21-95. gs :: view :: open Bramlette, M. N. & Wilcoxon, J. A. (1967). Middle Tertiary calcareous nannoplankton of the Cipero section, Trinidad, W.I. Tulane Studies in Geology and Paleontology. 5: 93-131. gs :: view :: open Dunkley Jones, T., Bown, P. R. & Pearson, P. (2009). Exceptionally well preserved upper Eocene to lower Oligocene calcareous nannofossils (Prymnesiophycidae) from the Pande Formation (Kilwa Group), Tanzania. Journal of Systematic Palaeontology. 7(4): 359-411. gs :: :: Fioroni, C., Villa, G., Persico, D. & Jovane, L. (2015). Middle Eocene-Lower Oligocene calcareous nannofossil biostratigraphy and paleoceanographic implications from Site 711 (equatorial Indian Ocean). Marine Micropaleontology. 118: 50-62. gs :: :: Müller, C. (1974). Calcareous nannoplankton, Leg 25 (Western Indian Ocean). Initial Reports of the Deep Sea Drilling Project. 25: 579-633. gs :: :: Perch-Nielsen, K. (1985). Cenozoic calcareous nannofossils. In, Bolli, H. M. , Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge 427-555. gs :: :: Shamrock, J. L. & Watkins, D. K. (2012). Eocene calcareous nannofossil biostratigraphy and community structure from Exmouth Plateau, Eastern Indian Ocean (ODP Site 762). Stratigraphy. 9(1): 1-11. gs :: :: References:
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Sphenolithus pseudoradians compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 6-7-2020
Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=1316 Go to Archive.is to create a permanent copy of this page - citation notes |