Stradnerlithus


Classification: Mesozoic -> Stephanolithiales -> Stephanolithiaceae -> Stradnerlithus
Sister taxa: Corollithion, Cylindralithus, Darwinilithus, Paralithella, Rectocorona, Rhombolithion, Rotelapillus, Stephanolithion, Stoverius, Stradnerlithus, Thurmannolithion, Truncatoscaphus,

Distinguishing features: Elliptical to diamond-shaped; rims low, narrow, unicyclic; central-area spanned by bars, radiating from central node or a longitudinal bar, usually spine bearing; typically small fragile and inconspicuous in LM.


Daughter taxa: (blue => in age window 0-800Ma)
Elliptical murolith with narrow rim and wide central area spanned by diagonal cross bars.
Narrowly elliptical/lenticular murolith with narrow rim and central area spanned by diagonal cross bars.
Stradnerlithus with central area spanned by 6 radial bars; 2 along short axis, 4 diagonal.
Described by Black (1971) as having 6 unequally spaced central area bars some of which curve. Arguably a junior synonym of S. geometricus.
Stradnerlithus with 6 central area bars that meet at a longitudinal structure.
Stradnerlithus with 6 robust central area bars and short, broad, central spine
Stradnerlithus with central area spanned by 6 bars that join at a longitudinal structure.
Gracile, elliptical Stradnerlithus with central area spanned by  6 bars (4 diagonal and 2 longitudinal).
Elliptical Stradnerlithus with eight, non-axial, central area bars.
Stradnerlithus with central area spanned by a longitudinal bar and 6 lateral bars (8 bars total, delimiting 8 holes).
Gracile Stradnerlithus with central area spanned by 8 radial bars.
Stradnerlithus with central area spanned by 10 cross bars that run from the mid-point of each side.
Narrowly elliptical Stradnerlithus with central area spanned by a longitudinal bar and ~12 lateral bars (delimiting ~14 holes).
Minute (ca 1.8µm), narrowly elliptical Stradnerlithus with central area spanned by a longitudinal bar and ~12 lateral bars (delimiting 12 holes).
Stradnerlithus with high, narrow rim and central area spanned by a longitudinal bar and numerous (~16-22) lateral bars.
Very small, with ca. 12 lateral bars per side and longitudunal bar
About 12 short lateral bars and perforate central plate.
Elliptical Stradnerlithus with multiple (~22) radial bars and a central spine. Inconspicuous but distinctive appearance in LM XPL with narrow rim and weakly birefringent central area bars/plate.
Specimens not identified to species level

Taxonomy:

Citation: Stradnerlithus Black, 1971
Rank: Genus
Type species: Stradnerlithus comptus Black, 1971.
Synonyms:

Farinacci & Howe catalog pages: Diadozygus * Nodosella * Stradnerlithus + *

Distinguishing features: Elliptical to diamond-shaped; rims low, narrow, unicyclic; central-area spanned by bars, radiating from central node or a longitudinal bar, usually spine bearing; typically small fragile and inconspicuous in LM.


Morphology remarks: Protolith coccoliths with low, narrow rims and a central-area spanned by bars, which typically radiate from a central point or from a longitudinally positioned bar. The coccoliths are typically small and fragile, dark, unicyclic and inconspicuous in XPL, and may have polygonal outlines. The upper surface of the rim is often crenulate. Central structure is usually spine bearing.

Geological Range:
Notes: Typically only present when preservation is good and so reported stratigraphic ranges are often discontinuous.
Last occurrence (top): within Maastrichtian Stage (66.04-72.05Ma, top in Maastrichtian stage). Data source: Total of range of species in this database
First occurrence (base): within Pliensbachian Stage (182.70-190.82Ma, base in Pliensbachian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Black, M., (1971). Coccoliths of the Speeton Clay and Sutterby Marl. Proceedings of the Yorkshire Geological Society, 38: 381-424.

Black, M., (1973). British Lower Cretaceous Coccoliths. I-Gault Clay (Part 2). Palaeontographical Society Monograph, 127: 49-112.

Bown, P.R. & Cooper, M.K.E., (1998). Jurassic. In: Bown, P.R. (Editor), Calcareous nannofossil biostratigraphy. British Micropalaeontological Society Publication Series. Chapman & Hall, pp. 34-85.

Burnett, J.A., (1998). Upper Cretaceous. In: Bown, P.R. (Editor), Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publications Series. Chapman & Hall, London, pp. 132-199.

Goy, G.; Noël, D. & Busson, G., (1979). Les conditions de sédimentation des schistes-carton (Toarcien inf.) du bassin de Paris déduites de l'étude des nannofossiles calcaires et des diagraphies. Documents de Géologie de la Faculté des Sciences de Lyon, 75: 33-57.

Rood, A.P.; Hay, W.W. & Barnard, T., (1971). Electron Microscope Studies of Oxford Clay Coccoliths. Eclogae Geologicae Helvetiae, 64: 245-272.

Rood, A.P.; Hay, W.W. & Barnard, T., (1973). Electron microscope studies of Lower and Middle Jurassic coccoliths. Eclogae Geologicae Helvetiae, 66: 365-382.

Worsley, T.R., (1971). Calcareous nannofossil zonation of Upper Jurassic and Lower Cretaceous sediments from the Western Atlantic. In: Farinacci, A. (Editor), Proceedings of the Second Planktonic Conference Roma 1971. 2 Edizioni Tecnoscienza, Rome, pp. 1301-1321.


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Stradnerlithus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 18-1-2019

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