Taxonomy
Original description: Initial one-half to two-thirds of test biserial, in later stage becoming multiserial due to chamber proliferation, resulting in a conically-shaped test; in lateral view, multiserial portion of test consisting of chambers lying in two or three planes only; top view of test broadly ovate to circular, consisting of from four to eight globular chambers; initial three or four pairs of chambers indistinct; flattened, increasing gradually in size, becoming strongly inflated and increasing rapidly in size in the median portion of the test; terminal chambers large, globular, strongly inflated, increasing slightly, or showing no increase in size as added; sutures initially flush to slightly depressed, becoming curved and deeply depressed; wall coarsely perforate and costate; pores closely spaced, aligned in three to four irregular vertical columns in intercostal areas; costae massive, highly raised, widely spaced, vertically arranged in a discontinuous pattern on chamber surfaces; each terminal chamber possessing a basal, rather wide and highly arched aperture opening into the central portion of the test; apertures covered by ponticuli in well-preserved specimens.
Entries in the Catalog of original descriptions: Racemiguembelina powelli
Character matrix
test outline: | Subtriangular | chamber arrangement: | Multiserial | edge view: | Equally biconvex | aperture: | Multiple |
sp chamber shape: | Inflated | coiling axis: | N/A | periphery: | N/A | aperture border: | Thin porticus |
umb chbr shape: | Inflated | umbilicus: | N/A | periph margin shape: | Broadly rounded | accessory apertures: | N/A |
spiral sutures: | Strongly depressed | umb depth: | N/A | wall texture: | Coarsely costate | shell porosity: | Macroperforate: >2.5µm |
umbilical or test sutures: | Strongly depressed | final-whorl chambers: | 4-6 | 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 G. gansseri zone (71.73-73.80Ma, base in Campanian stage). Data source: [copied from Chronos database]
Plot of range and occurrence data:
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 Smith, C. C. & Pessagno, E. A. (1973). Planktonic foraminifera and stratigraphy of the Corsicana formation (Maestrichtian) North-central Texas. Cushman Foundation for Foraminiferal Research, Special Publication. 12: 1-67. gs OReferences:
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Racemiguembelina powelli compiled by the pforams@mikrotax project team viewed: 14-2-2025
Short stable page link: https://mikrotax.org/pforams/index.php?id=110483 Go to Archive.is to create a permanent copy of this page - citation notes |
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