Distinguishing features: Parent taxon (ntax_mesozoic): Mesozoic nannofossils - Cenozoic and extant taxa are in a separate module This taxon: Murolith coccoliths with a distal/outer cycle of non-imbricating elements, i.e., in side view, the sutures are vertical or near-vertical.
Daughter taxa (time control age-window is: 0-800Ma)
Granddaughter taxa
Parhabdolithaceae Murolith (protolith type) coccoliths with bicylic rims and central-areas spanned by an axial-cross or transverse bar bearing a broad, often long, spine.
Stephanolithiaceae 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.
Citation: Stephanolithiales Bown & Young, 1997Taxonomic rank: orderTaxonomic discussion: The order Stephanolithiales probably gave rise to the Order Syracosphaerales, since Calciosolenia is very similar to various Stephanolthaceae genera and early Syracosphaera species are similar to Stradnerlithus. This is also compatible with molecular gentic data since the Syracosphaerales appear to have diverged from he other coccolithophres in the basal radiatition of the group (i.e. in the Early Jurassic). So, it may well prove useful to subsume the Stephanolithiales into the Syracosphaerales, see also discussion in Bown et al. (2017)
Distinguishing features: Parent taxon (ntax_mesozoic): Mesozoic nannofossils - Cenozoic and extant taxa are in a separate module This taxon: Murolith coccoliths with a distal/outer cycle of non-imbricating elements, i.e., in side view, the sutures are vertical or near-vertical.
Morphology: Muroliths with a distal/outer-cycle composed of non-imbricating elements, i.e. in side view, the sutures are vertical or near vertical. This feature is not distinguishable from imbrication in the LM. The term protolith is applied to this rim structure (Bown, 1987). The order comprises (1) the Parhabdolithaceae a group of murolith coccoliths typified by thick, robust, high walls, which are characteristic component of Early Jurassic nannofloras, and (2) the Stephanolithaceae which have similar wall-structure but a more diverse range of morphologies and which occur throughout the Jurassic and Cretaceous. Crystallographically the rims consist of an outer cycle of V-units and inner cycle of R-units, giving a bicyclic apearnce in cross-polars. The central structures are disjunct, and most often show low birefringence.
Geological Range: Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Danian stage). Data source: Total of ranges of the species in this database First occurrence (base): within NT2b subzone (194.83-218.41Ma, base in Norian stage). Data source: Total of ranges 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: ntax_mesozoic
References:
Bown, P. R. & Young, J. R. (1997). Mesozoic calcareous nannoplankton classification. Journal of Nannoplankton Research. 19(1): 21-36. gs
Bown, P. R. (1987a). Taxonomy, evolution, and biostratigraphy of Late Triassic-Early Jurassic calcareous nannofossils. Special Papers in Palaeontology. 38: 1-118. gs
Bown, P. R. (1998b). Triassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 29-33. gs
Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Lower Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 86-131. gsO
Bown, P. R., Lees, J. A. & Young, J. R. (2017). On the Cretaceous origin of the Order Syracosphaerales and the genus Syracosphaera. Journal of Micropalaeontology. 36(2): 153-165. gs
Young, J. R. & Bown, P. R. (1997). Proposals for a revised classification system for calcareous nannoplankton. Journal of Nannoplankton Research. 19(1): 15-47. gs
Stephanolithiales compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 20-1-2025
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