Nannotax3 - ntax_cenozoic - Umbellosphaera tenuis

Nannotax3 - ntax_cenozoic - Umbellosphaera tenuis Nannotax3 - ntax_cenozoic - Umbellosphaera tenuis

Umbellosphaera tenuis

Classification: ntax_cenozoic -> Coccolith families inc sed -> Umbellosphaeraceae -> Umbellosphaera -> Umbellosphaera tenuis
Sister taxa: U. tenuis, U. irregularis, U. sp.

Yang et al 2012 pl15a.JPG
Yang et al 2012 pl15b.JPG
Reid 1980 pl4 06.jpg
Reid 1980 pl4 07.jpg
JRYlm AMT18 CTD67 z301.jpg
JRYlm AMT18 CTD67-0m z303.jpg
JRYlm AMT18-CTD76 30m z012.jpg
JRYlm-figStn 53 0m x100 x1,6 009.JPG
Heimdal & Gaarder 1981 pl11 f59a.JPG
Samtleben 1978 pl2 07.JPG
Muller74Leg25-pl3-2.JPG
Young_etal_2003_99-34.JPG
Young1998_pl05_fig30.JPG
Young1998_umbellosphaera_tenuis.jpg

Sub-taxa & variants (time control age-window is: 0-800Ma)
				Umbellosphaera tenuis type I Coccoliths with distinct sutural ridges and numerous finer papillate secondary ridges
				Umbellosphaera tenuis type II Sutural and secondary ridges papillate.
				Umbellosphaera tenuis type IIIa Sutural and secondary ridges heavily calcified and not clearly separable. Central area closed by inward extensions of the sutural rides.
				Umbellosphaera tenuis type IIIb Sutural and secondary ridges heavily calcified but well-separated, 2-4 secondary ridges per element. Central area open.
				Umbellosphaera tenuis type IV Sutural ridges well calcified near centre of coccolith, lower toward periphery. Numerous secondary ridges, often anastamosing.
				Umbellosphaera tenuis type O Cocoliths smooth - resemble U. irregulars in distal view but have the characteristic convex profile of U. tenuis. Liths are often very thin/weakly calcified.

Taxonomy:

Citation: Umbellosphaera tenuis (Kamptner 1937) Paasche in Markali & Paasche, 1955

taxonomic rank: Species

Basionym: Coccolithus tenuis Kamptner 1937

Synonyms:

Ellipsodiscoaster lidzii Boudreaux and Hay, 1969
Discoaster murrayi Black & Barnes 1961

Variants: Variation: The morphology of this species is very variable, in terms of ridge thickness, presence of papillae (nodes) on the ridges, number of secondary ridges, degree of bimodality in ridge thickness. Kleijne (1993) distinguished several types of U. tenuis. This work has not been followed up by a detailed study and these types are arguably intergradational. Nonetheless, most specimens are readily assignable to a single type, so it seems possible that they will prove to be discrete (sub) species. (NB Subdivision of type II into IIa Iand IIb is from Young et al. 2003)

Type O smooth - cocoliths resemble U. irregularis in distal view but have the characteristic convex profile of U. tenuis
Type I - coccoliths with distinct sutural ridges and numerous finer papillate secondary ridges.
Type II - sutural and secondary ridges papillate.
Type IIIa - sutural and secondary ridges heavily calcified and not clearly separable. Central area closed by inward extensions of the sutural rides.
Type IIIb - sutural and secondary ridges heavily calcified but well-separated, 2-4 secondary ridges per element. Central area open
Type IV - sutural ridges well calcified near centre of coccolith, lower toward periphery. Numerous secondary ridges, often anastamosing.

Taxonomic discussion: This form is substantially more robust than U. irregularis and is much more common in the fossil record.

Distinguishing features:
Parent taxon (Umbellosphaera): Coccoliths trumpet-shaped
This taxon: Coccoliths convex outwards, relatively heavily calcified, with ridges on the distal surface.

Farinacci & Howe catalog pages: C. tenuis * , E. lidzi * , D. murrayi *

Morphology:

Liths convex distally; distal surface usually with pattern of ridges; major ridges sub-radial running along sutures; secondary ridges diverge anticlockwise from them.
Proxmil shield is normally narrow, often missing, and dificult to detect in LM.

Search data:

LITHS: placolith, asymmetric, elliptical, CA: ca_conjunct, closed, plate,
CSPH: equant, BC-dimorphic, CROSS-POLARS: R-prominent, rim-unicyclic,

Lith size: 2->9µm; Coccosphere size: 8->12µm; Liths per sphere: 15->25
Data source notes: lith size from Kleijne 1993; lith numbers from Yang & Wei 2003, range inferred from single estimate

The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: U. tenuis is much less common in Holocene sediments than in the plankton, probably because the coccoliths readily disintegrate and dissolve. They are nonetheless reasonably frequent in the Quaternary, but there are few pre-Pliocene records. It is conceivable that they have become more abundant since extinction of the discoasters which may have occupied a similar ologitrophic niche.
Last occurrence (top): Extant. Data source: present in the plankton (Young et al. 2003)
First occurrence (base): within NN15 zone (3.70-3.92Ma, base in Zanclean stage). Data source: Young (1998)

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
Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
Taxon plotted: Umbellosphaera tenuis, synonyms included - Ellipsodiscoaster lidzii; Umbellosphaera tenuis;
See also space-time plot :: Samples map :: Parent: Umbellosphaera

References:

Black, M. & Barnes, B. (1961). Coccoliths and discoasters from the floor of the South Atlantic Ocean. Journal of the Royal Microscopical Society. 80: 137-147. gs

Boudreaux, J. E. & Hay, W. W. (1969). Calcareous nannoplankton and biostratigraphy of the late Pliocene-Pleistocene-Recent sediments in the Submarex cores. Revista Española de Micropaleontología. 1(3): 249-292. gs O

Heimdal, B. R. & Gaarder, K. R. (1981). Coccolithophorids from the northern part of the eastern central Atlantic II. Heterococcolithophorids. “Meteor” Forschungsergebnisse. 33: 37-69. gs

Kamptner, E. (1937). Neue und bemerkenswerte Coccolithineen aus dem Mittelmeer. Archiv für Protistenkunde. 89: 279-316. gs

Kleijne, A. (1993b). Morphology, Taxonomy and distribution of extant coccolithophorids (Calcareous nannoplankton). PhD Thesis, Vrije Universiteit Amsterdam. 1-321. gs

Müller, C. (1974). Calcareous nannoplankton, Leg 25 (Western Indian Ocean). Initial Reports of the Deep Sea Drilling Project. 25: 579-633. gs

Reid, F. M. H. (1980). Coccolithophorids of the North Pacific Central Gyre with notes on their vertical and seasonal distribution. Micropaleontology. 26(2): 151-176. gs

Samtleben, C. (1978). Pliocene-Pleistocene coccolith assemblages from Sierra Leone Rise - Site 366, Leg 41. Initial Reports of the Deep Sea Drilling Project. 41(16): 913-931. gs

Yang, T. -N., Wei, K. & Wu, J. -T. (2012). Marine coccolithophores around Taiwan. Biodiversity Research Center, Academica Sinica, Taipei. 1-96. gs

Young, J. R. (1998). Neogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 225-265. gs

Young, J. R., Geisen, M., Cros, L., Kleijne, A., Probert, I. & Ostergaard, J. B. (2003). A guide to extant coccolithophore taxonomy. Journal of Nannoplankton Research. S1: 1-132. gs