Distinguishing features:
Parent taxon (Prediscosphaeraceae): 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.
This taxon: Prediscosphaera with massive, blocky spine covering most of the distal surface.
Daughter taxa (time control age-window is: 0-800Ma) | ||||
 |  |  |  | Petrarhabdus copulatus Prediscosphaera with massive, four-part, blocky, square spine covering most of the distal surface. |
 |  |  |  | Petrarhabdus kirenii |
 |  |  |  | Petrarhabdus vietus >A species of Petrarhabdus in which the spine is significantly smaller than the coccolith. In the LM, the image is very highly birefringent. In the SEM, the spine appears to be composed of three stacks of calcite blocks. |
| Petrarhabdus sp. Specimens not identified to species level | ||||
Taxonomy:
Farinacci & Howe catalog pages: Petrarhabdus *
Distinguishing features:
Parent taxon (Prediscosphaeraceae): 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.
This taxon: Prediscosphaera with massive, blocky spine covering most of the distal surface.
| Tags | LITHS: placolith, circular, elliptical, quadrate, CA: cross-axial, ca_disjunct, process, CROSS-POLARS: V-prominent, |
| Metrics | Lith size: 7->20µm; Data source notes: size range of included species |
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): at base of Cenomanian Stage (0% up, 100.5Ma, in Albian stage). Data source: Total of range of species in this database
Plot of occurrence data:
Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 132-199. gs V O Deflandre, G. (1959). Sur les nannofossiles calcaires et leur systématique. Revue de Micropaléontologie. 2: 127-152. gs Wise, S. W. (1983). Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP Leg 71 in the Falkland Plateau region, Southwest Atlantic Ocean. Initial Reports of the Deep Sea Drilling Project. 71: 481-550. gs V OReferences:
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Petrarhabdus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 7-12-2021
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10889 Go to Archive.is to create a permanent copy of this page - citation notes |
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