Distinguishing features: Parent taxon (Stephanolithiales): Murolith coccoliths with a distal/outer cycle of non-imbricating elements, i.e., in side view, the sutures are vertical or near-vertical. This taxon: 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 (time control age-window is: 0-800Ma)
Granddaughter taxa
Cylindralithus Circular or sub-circular with high, sculpted, wall; central-area vacant or with cross bars.
Stephanolithion Elliptical and often polygonal; rims low but broad, bicyclic; central-area spanned by one to eight bars; prominent spines protrude from the rim
Stradnerlithus 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.
Truncatoscaphus Polygonal (subhexagonal), often elongate and narrow; muroliths with central area spanned by a longitudinal bar and 6 or more lateral bars.
Citation: Stephanolithiaceae Black 1968Rank: Family Taxonomic discussion: The family as originally described by Black (1968) included only Stephanolithion. The concept of the family was broadened by Black (1973).
Distinguishing features: Parent taxon (Stephanolithiales): Murolith coccoliths with a distal/outer cycle of non-imbricating elements, i.e., in side view, the sutures are vertical or near-vertical. This taxon: 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: 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.
Search data:
Tags
LITHS: murolith, ca_disjunct,
Metrics
Lith size: 0->0µm;
The morphological data given here can be used on the advanced search page. See also these notes
Geological Range: Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Danian stage). Data source: Total of range of species in this database First occurrence (base): in lower part of Pliensbachian Stage (21% up, 189.1Ma, in Pliensbachian 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: Stephanolithiales
References:
Black, M. (1968). Taxonomic problems in the study of coccoliths. Palaeontology. 11: 793-813. gsVO
Black, M. (1973). British Lower Cretaceous Coccoliths. I-Gault Clay (Part 2). Palaeontographical Society Monograph. 127: 49-112. gs
Bown, P. R. & Cooper, M. K. E. (1998). Jurassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 34-85. gs
Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Early Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 86-131. gs
Stephanolithiaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 24-10-2021
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