Taxonomy
Original description: This form is similar to G. fornicata ackermanni, but the Rugoglobigerina habitus is more developed. The test is slightly convex, the chambers are inflated, subangular, with the inflation more pronounced on the umbilical side, so that the faintly beaded double keel (narrow peripheral band) is not exactly in the middle of the chamber, but shifted more toward the dorsal side. The chambers, 4-5 in the last whorl, ar slightly more elongated; the sutures bcome radial in the last chambers; the test is rough, especially in the early stages, and the umbilicus is narrower. The test is dextrally coiled.
Entries in the Catalog of original descriptions: Globotruncana (Rugoglobigerina) circumnodifer subcircumnodifer, Globotruncana japonica robusta, Globotruncana japonica
Character matrix
test outline: | Lobate | chamber arrangement: | Trochospiral | edge view: | Planoconvex | aperture: | Umbilical |
sp chamber shape: | Petaloid | coiling axis: | Low | periphery: | Double keel | aperture border: | Tegilla |
umb chbr shape: | Trapezoidal | umbilicus: | Narrow | periph margin shape: | Moderately rounded | accessory apertures: | Infralaminal |
spiral sutures: | Moderately depressed | umb depth: | Deep | wall texture: | Finely pustulose | shell porosity: | - |
umbilical or test sutures: | Moderately depressed | final-whorl chambers: | 4-5 | N.B. These characters are used for advanced search. N/A - not applicable |
Geological Range:
Last occurrence (top): within P. hariaensis zone (66.39-67.64Ma, top in Maastrichtian stage). Data source: [copied from Chronos database]
First occurrence (base): within R. calcarata zone (75.06-75.91Ma, base in Campanian stage). Data source: [copied from Chronos database]
Plot of range and occurrence data:
Caron, M. (1985). Cretaceous planktic foraminifera. In, Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. CUP, Cambridge 17-86. gs Gandolfi, R. (1955). The genus Globotruncana in northeastern Colombia. Bulletins of American Paleontology. 36: 1-118. gs Pessagno, E. A. (1967). Upper Cretaceous planktonic foraminifera from the western Gulf Coastal Plain. Palaeontographica Americana. 5: 245-445. gs OReferences:
Rugotruncana subcircumnodifer compiled by the pforams@mikrotax project team viewed: 14-11-2024
Short stable page link: https://mikrotax.org/pforams/index.php?id=110514 Go to Archive.is to create a permanent copy of this page - citation notes |
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