Nannotax3 - ntax_cenozoic - S. furcatolithoides group

S. furcatolithoides group

Classification: ntax_cenozoic -> Discoasterales -> Sphenolithaceae -> Sphenolithus -> S. furcatolithoides group
Sister taxa: S. capricornutus group, S. dissimilis group, S. moriformis group, S. heteromorphus group, S. predistentus group, S. furcatolithoides group, S. radians group, S. conspicuus group, S. sp.

Daughter taxa (time control age-window is: 0-800Ma)
				Sphenolithus cuniculus forms with low basal quadrants (‘feet’) and ~90° bifurcations
				Sphenolithus furcatolithoides Spines diverge just above the base and are near-parallel in the lower part
				Sphenolithus kempii square base with 3 or 4 spines
				Sphenolithus perpendicularis square base with two spines that diverge by around 90°
				Sphenolithus cf. S. perpendicularis tapering base with narrow, high-angled lateral spines;
				Sphenolithus strigosus duocrystalline spines that bifurcate high-up on the spine.

Taxonomy:

Citation: Sphenolithus furcatolithoides group sensu Bown & Dunkley Jones, 2012

Rank: species group

Distinguishing features: Small Middle Eocene sphenoliths with duocrystaline spines that are dark in the 45° position.

Farinacci & Howe catalog pages:

Morphology: Included within the S. radians group by Bown & Dunkley Jones (2012), these species are characterised by two (rarely more) bifurcating apical spines, bright at 0° and dark at 45°, extending from the upper quadrants. Species differentiation is based on the height and angle of spine bifurcation and size of the basal quadrants. In moderate to poor preservation the upper portion of these tall spines is usually lost, but when well preserved, as seen herein, the entire lith may be preserved, highlighting the extreme spine lengths (up to 25μm; Pl. 11, fig. 25) and variations in upper spine morphology. In the slightly younger, and probably descendant, S. predistentus group, only the lower quadrants are clearly discernable in the basal column and the spines are bright at 45° and diverge in the uppermost part of the spine (e.g. S. obtusus, S. runus, S. predistentus). [Bown & Newsam 2017]

Search data:

Tags	LITHS:
Metrics	Lith size: 2->17µm;

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

Geological Range:
Last occurrence (top): in lower part of Bartonian Stage (22% up, 40.4Ma, in Bartonian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Lutetian Stage (0% up, 47.8Ma, in Lutetian 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:

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 V O

S. furcatolithoides group compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 14-4-2021

Taxon Search:

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=1213 Go to Archive.is to create a permanent copy of this page - citation notes

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