Daughter taxa (time control age-window is: 0-800Ma)
Granddaughter taxa
Lapideacassis Hemispherical to cylindrical nannoliths, with walls constructed from one to several cycles of thin elements, enclosing a hollow central space; the nannolith tapers distally, and may have long apical spines or processes. Species arranged here by number of spines.
Citation: Lapideacassaceae Bown & Young, 1997Rank: FamilyTaxonomic discussion: Rare and sporadic stratigraphic distribution, but Cretaceous/Tertiary boundary survivor.
Distinguishing features: Parent taxon (Nannolith families inc sed): Haptophytes forming calcareous structures not obviously homologous with heterococcoliths, holococcoliths, or discoasteralids This taxon: Hemispherical to cylindrical nannoliths, with walls constructed from one to several cycles of thin elements, enclosing a hollow central space; the nannolith tapers distally, and may have long apical spines or processes.
Morphology: Crystallographic orientations: The entire nannolith is formed of R-units, in side view the c-axes are inclined upward slightly (so with gypsum plate when vertical the left hand side is blue and the right hand side yellow). In apical view the c-axes are slightly oblique from radial. [JRY 2017 my obs, and interpretation of published micrographs]
Search data:
: hollow,
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): in lower part of Tortonian Stage (17% up, 10.9Ma, in Tortonian stage). Data source: Total of range of species in this database First occurrence (base): at base of Aptian Stage (0% up, 126.3Ma, in Aptian 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: Nannolith families inc sed
References:
Bown, P. R. & Young, J. R. (1997). Mesozoic calcareous nannoplankton classification. Journal of Nannoplankton Research. 19(1): 21-36. gsVO
Kennedy, W. J. et al. (2000). Integrated stratigraphy across the Aptian-Albian boundary in the Marnes Bleues, at the Col de Pre _-Guittard, Arnayon (Drome), and at Tartonne (Alpes-de-Haute-Provence), France: a candidate Global Boundary Stratotype Section and Boundary Point for the base of the Albian Stage. Cretaceous Research. 21: 591-720. gs
Lapideacassaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 21-3-2023
Comments
(0)