Distinguishing features: Regular placoliths; central area spanned by cross-bars supporting a tall, complexely-constructed spine.
The distal shield and proximal shield constructed from 16 large non-imbricating elements (V-units); R-units form restricted cycle on proximal shield and inner tube cycle, giving bicyclic LM image with bright inner cycle.
Daughter taxa (time control age-window is: 0-800Ma)![]() | Granddaughter taxa | ||||
![]() | ![]() | Petrarhabdus Prediscosphaera with massive, blocky spine covering most of the distal surface. | |||
![]() | Prediscosphaera |
Taxonomy:
Farinacci & Howe catalog pages: Prediscosphaeraceae [no catalog entry yet]
Distinguishing features: Regular placoliths; central area spanned by cross-bars supporting a tall, complexely-constructed spine.
The distal shield and proximal shield constructed from 16 large non-imbricating elements (V-units); R-units form restricted cycle on proximal shield and inner tube cycle, giving bicyclic LM image with bright inner cycle.
Tags | LITHS: placolith, ca_disjunct, |
Metrics | Lith size: 0->0µm; |
Geological Range:
Notes: Common components of Upper Cretaceous assemblages.
Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Maastrichtian 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:
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 Jordan, R. W. & Young, J. R. (1990). Proposed changes to the classification system of living Coccolithophorids. INA Newsletter. 12(1): 15-18. gs V O Norris, R. E. (1983). The family position of Papposphaera Tangen and Pappomonas Manton & Oates (Prymnesiophyceae) with records from the Indian Ocean. Phycologia. 22(2): 161-169. gs Rood, A. P., Hay, W. W. & Barnard, T. (1971). Electron Microscope Studies of Oxford Clay Coccoliths. Eclogae Geologicae Helvetiae. 64: 245-272. gs V O Vekshina, V. N. (1959). Coccolithophoridae of the Maastrichtian deposits of the West Siberian lowlands. Trudyi Instituta Geologii i Geogiziki, Sibiriskoe Otlodelenie, Akademiya Nauk SSSR (Nauka) Moscow. 2: 56-81. gsReferences:
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Prediscosphaeraceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 22-4-2021
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