pforams@mikrotax - Spiroplecta americana

Spiroplecta americana

Classification: pf_mesozoic -> Heterohelicidae -> Spiroplecta -> Spiroplecta americana
Sister taxa: S. americana, S. sp.


Citation: Spiroplecta americana Ehrenberg 1844
Rank: Species
Basionym: Spiroplecta americana

Type images:

Original description: "Test minute and subtriangular in side view, the biserial portion flaring widely from the tiny planispiral coil, periphery broadly rounded; the 5-6 chambers of the coil are low and not much inflated, the later 6-11 biserially arranged chambers increasing rapidly in height so that later ones are inflated and subglobular; sutures distinct, straight, somewhat oblique, depressed; wall calcareous, hyaline, surface faintly striate, finely perforate; aperture a low arch at the inner margin of the final chamber, sometimes with a slight lip."

Entries in the Catalog of original descriptions: Spiroplecta americana, Heterohelix navarroensis

Emended description:


Wall type:


Character matrix
test outline:Subtriangularchamber arrangement:Biserialedge view:Compressedaperture:Interiomarginal
sp chamber shape:Inflatedcoiling axis:N/Aperiphery:N/Aaperture border:Thin flange
umb chbr shape:Inflatedumbilicus:N/Aperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:N/Awall texture:Finely costateshell porosity:-
umbilical or test sutures:Moderately depressedfinal-whorl chambers:2.0-2.0 N.B. These characters are used for advanced search. N/A - not applicable

Geological Range:
Last occurrence (top): within P. hariaensis zone (66.39-67.30Ma, top in Maastrichtian stage). Data source: [copied from Chronos database]
First occurrence (base): within R. calcarata zone (75.71-76.18Ma, base in Campanian stage). Data source: [copied from Chronos database]

Plot of range and occurrence data:


Ehrenberg, C. G. (1844). Über 2 neue Lager von Gebirgsmassen aus Infusorien als Meers-Absatz in Nord-Amerika und eine Vergleichung derselben mit den organischen Kreidegebilden in Europa und Afrika. Bericht uber die zu Bekanntmachung geeigneten Verhandlungen der Koniglichen Preussische Akademie der Wissenschaften zu Berlin. 57-97. gs

Nederbragt, A. J. (1991). Late Cretaceous biostratigraphy and development of Heterohelicidae (planktic foraminifera). Micropaleontology. 37: 329-372. gs

Pessagno, E. A. (1967). Upper Cretaceous planktonic foraminifera from the western Gulf Coastal Plain. Palaeontographica Americana. 5: 245-445. gs V O

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 V O


Spiroplecta americana compiled by the pforams@mikrotax project team viewed: 29-9-2022

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