arrayname: original
Taxonomy
Original description: The test has a lobate periphery and is flat or slightly convex on the dorsal side. The last chambers in many cases become slightly inflated dorsally, giving to the upper side of the test a somewhat uneven appearance. The side wall, which is limited by the marginal dorsal and ventral keels, also, in some specimens, appears slightly convex in the last chambers. The ventral side of the test is concave, but the last chambers are, as on the dorsal side, in many specimens more or less inflated. Chambers of the last whorl do not always follow one another uniformly, some being arranged more or less obliquely with respect to one another. The suture lines on the dorsal side are strongly curved, the initial parts clearly beaded and later very strongly developed. They are radial on the ventral side. The last whorl is usually formed by five chambers, but four are also common. Six chambers have been noted only in one specimen. The preservation of the specimens so far examined has not allowed detailed study of the aperture or apertures, which probably open into the umbilicus. A coverplate over the umbilicus with several apertures seems to be present, however, in some of the better preserved specimens.
Entries in the Catalog of original descriptions: Globotruncana mayaroensis, Globotruncana (Globotruncana) planata
Character matrix
test outline: | Subcircular | chamber arrangement: | Trochospiral | edge view: | Planoconvex | aperture: | Umbilical-extraumbilical |
sp chamber shape: | Inflated | coiling axis: | Low | periphery: | Double keel | aperture border: | Tegilla |
umb chbr shape: | Inflated | umbilicus: | Narrow | periph margin shape: | Subangular | accessory apertures: | None |
spiral sutures: | Raised beaded | umb depth: | Shallow | wall texture: | Smooth | shell porosity: | Finely Perforate: 1-2.5µm |
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): at top of P. hariaensis zone (100% up, 66.4Ma, in Maastrichtian stage). Data source: zonal marker (from Timescale Creator)
First occurrence (base): within A. mayaroensis zone (67.64-69.27Ma, base in Maastrichtian stage). Data source: [copied from Chronos database]
Plot of range and occurrence data:
Bolli, H. M. (1951b). The genus Globotruncana in Trinidad. Journal of Paleontology. 25(2): 187-199. gs Huber, B. T., Tur, N., Self-Trail, J. & MacLeod, K. G. (2022a). Calcareous plankton biostratigraphic fidelity and species richness during the last 10 m.y. of the Cretaceous at Blake Plateau, subtropical North Atlantic. Cretaceous Research. 131: 1-42. gs Pessagno, E. A. (1967). Upper Cretaceous planktonic foraminifera from the western Gulf Coastal Plain. Palaeontographica Americana. 5: 245-445. gs O Postuma, J. A. (1971). Manual of planktonic foraminifera. Elsevier for Shell Group, The Hague. 1-406. gs Robaszynski, F., Caron, M., Gonzales Donoso, J. M., Wonders, A. A. H. & the European Working Group on Planktonic Foraminifera (1984). Atlas of Late Cretaceous globotruncanids. Revue de Micropaléontologie. 26(3-4): 145-305. gsReferences:
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Abathomphalus mayaroensis compiled by the pforams@mikrotax project team viewed: 20-4-2025
Short stable page link: https://mikrotax.org/pforams/index.php?id=110003 Go to Archive.is to create a permanent copy of this page - citation notes |
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