Daughter taxa (time control age-window is: 0-800Ma)
Granddaughter taxa
Bomolithus Discoidal discoasteralids with a wide non-birefringent cycle and at least one narrower birefringent cycle, i.e., narrower than the diameter of the nannolith.
Citation: Heliolithaceae Hay & Mohler, 1967Rank: FamilyTaxonomic discussion: Group of nannoliths closely allied to the discoasters, and probably transitional between typically VR heterococcolith morphology and the more derived, single crystal-unit form of Discoaster.
Distinguishing features: Parent taxon (Discoasterales): Radially symmetrical nannoliths formed from one to several separate cycles of elements that radiate from a common centre or axis. This taxon: Discoidal discoasteralids with several distinct cycles including at least one that is birefringent.
The morphological data given here can be used on the advanced search page. See also these notes
Geological Range: Last occurrence (top): at base of Ypresian Stage (1% up, 55.9Ma, in Ypresian stage). Data source: Total of range of species in this database First occurrence (base): at base of Selandian Stage (4% up, 61.5Ma, in Selandian 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: Discoasterales
References:
Hay, W. W. & Mohler, H. P. (1967). Calcareous nannoplankton from Early Tertiary rocks at Point Labau, France and Paleocene-Early Eocene correlations. Journal of Paleontology. 41(6): 1505-1541. gs
Heliolithaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 21-3-2023
Comments
(0)