pforams@mikrotax - Racemiguembelina powelli pforams@mikrotax - Racemiguembelina powelli

Racemiguembelina powelli

Classification: pf_mesozoic -> Heterohelicidae -> Racemiguembelina -> Racemiguembelina powelli
Sister taxa: R. fructicosa, R. powelli, R. sp.


Citation: Racemiguembelina powelli Smith&Pessagno 1973
taxonomic rank: Species
Basionym: Racemiguembelina powelli

Type images:

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:Subtriangularchamber arrangement:Multiserialedge view:Equally biconvexaperture:Multiple
sp chamber shape:Inflatedcoiling axis:N/Aperiphery:N/Aaperture border:Thin porticus
umb chbr shape:Inflatedumbilicus:N/Aperiph margin shape:Broadly roundedaccessory apertures:N/A
spiral sutures:Strongly depressedumb depth:N/Awall texture:Coarsely costateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Strongly depressedfinal-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 O


Racemiguembelina powelli compiled by the pforams@mikrotax project team viewed: 22-7-2024

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