Stephanolithiaceae


Classification: Mesozoic -> Stephanolithiales -> Stephanolithiaceae
Sister taxa: Parhabdolithaceae, Stephanolithiaceae,

Short diagnosis: Murolith (protolith type) coccoliths with rims of non-imbricate V-units and weakly-developed, or vestigial, proximal/inner-cycles (R-units), with central-areas spanned by one to numerous bars. 


Daughter taxa (blue => in age window 0-300Ma) Granddaughter taxa
Polygonal, usually hexagonal; rim bicyclic; central area with 4-6 radial bars

Circular or sub-circular with high, sculpted, wall; central-area vacant or with cross bars.

Cylindrical nannofossil with median flange, a flaring cone on one side and a circlet of flaring spines on the other

Small elliptical stephanolithid; central area with bridge supporting a hollow spine and bars parallel to the long axis 

Elliptical murolith with non-imbricate wall and low spine supported by complex central structure

Diamond-shaped; rim unicyclic (stradnerlithids).

Subcircular to circular; rim high, narrow, bicyclic; central area spanned by radial bars; Short spines protrude from the rim

Elliptical and often polygonal; rims low but broad, bicyclic; central-area spanned by one to eight bars; prominent spines protrude from the rim

Narrowly elliptical to circular; rim low, bicyclic; central area wide, spanned by cross bars.

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.

Elliptical; rim narrow; central area with axial cross, numerous lateral bars and spine

Polygonal (subhexagonal), often elongate and narrow; muroliths with central area spanned by a longitudinal bar and 6 or more lateral bars.

Taxonomy:

Citation: Stephanolithiaceae Black 1968
Rank: Family
Notes & discussion: The family as originally described by Black (1968) included only Stephanolithion. The concept of the family was broadened by Black (1973). 

Farinacci & Howe catalog pages: Stephanolithiaceae [no catalog entry yet]

Short diagnosis: Murolith (protolith type) coccoliths with rims of non-imbricate V-units and weakly-developed, or vestigial, proximal/inner-cycles (R-units), with central-areas spanned by one to numerous bars. 


Morphology remarks: LM image is usually unicyclic and inconspicuous, although a number of genera do exhibit bicyclicity, e.g. Rotelapillus, Stephanolithion and Stoverius. Coccolith outlines may be polygonal.

Geological Range:
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., (1968). Taxonomic problems in the study of coccoliths. Palaeontology, 11: 793-813.

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.

Bown, P.R.; Rutledge, D.C.; Crux, J.A. & Gallagher, L.T., (1998). Early Cretaceous. In: Bown, P.R. (Editor), Calcareous nannofossil biostratigraphy. British Micropalaeontological Society Publication Series. Chapman & Hall, pp. 86-131.


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Stephanolithiaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 16-12-2017

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