Rotalipora cushmani var. evoluta

Classification: pf_mesozoic -> Rotaliporidae -> Rotalipora -> Rotalipora cushmani -> Rotalipora cushmani var. evoluta
Sister taxa: R. cushmani var. evoluta


Citation: Rotalipora cushmani var. evoluta (Sigal, 1948)
Rank: variety
Basionym: Rotalipora cushmani var. evoluta
Taxonomic discussion: Origininally described as R. cushmani var. evoluta
Not in Ellis and Messina for some reason, but Todd Library has Sigals reprint. [copied from Chronos database]

Type images:

Original description: Translated from French: This species displays a tendency to become uncoiled in the last whorl, an impression reinforced by a more rapid increase in the size of the chambers than in the preceding species (Rotalipora cushmani (Morrow ) = Globorotalia cushmani Morrow, 1934). In addition, the chambers are less globular, more overlapping and separated by less deep sutural depressions; the sutural aperture is located next to the umbilicus, at the start of the calcareous deck and may also be positioned as in the following species (Rotalipora globotruncanoides Sigal and Thalmanninella brotzeni, Sigal, 1948), but unlike them, among others differences, the chambers do not have the same arched look. Sinistral or dextral coiling.

Cette espèce montre, au dernier tour, une tendance au déroulement, impression accrue par une croissance beaucoup plus rapide des loges que dans l'espèce précédente [Rotalipora cushmani (Morrow) = Globorotalia cushmani Morrow, 1934]. Les loges sont aussi moins globuleuses, plus chevauchantes et séparées par des dépressions suturales moins profondes; l'ouverture suturale se situe près de l'ombilic, à la naissance du pont calcaire et arrive même à présenter presque la disposition de celle des espèces suivantes [Rotalipora globotruncanoides Sigal and Thalmanninella brotzeni Sigal, 1948]; mais, à leur différence, entre autres, les loges n'ont pas la même allure arquée . Sénestres et dextres.

Entries in the Catalog of original descriptions: Rotalipora cushmani evoluta

Geological Range:
Last occurrence (top): within R. cushmani zone (94.03-95.94Ma, top in Cenomanian stage). Data source: [copied from Chronos database]
First occurrence (base): within T. globotruncanoides zone (96.08-100.50Ma, base in Cenomanian stage). Data source: [copied from Chronos database]

Plot of range and occurrence data:

Character matrix

test outline:Ovatechamber arrangement:Trochospiraledge view:Compressedaperture:-
sp chamber shape:Petaloidcoiling axis:Lowperiphery:Single keelaperture border:Thin lip
umb chbr shape:Subtriangularumbilicus:Narrowperiph margin shape:Subangularaccessory apertures:Sutural
spiral sutures:Raised beadedumb depth:Shallowwall texture:Finely pustuloseshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:5.0-7.0 N.B. These characters are used for advanced search. N/A - not applicable


Sigal, J. (1948). Notes sur les genres de foraminiferes Rotalipora Brotzen 1942 et Thalmanninella Famille des Globorotaliidae. Revue de l'Institut Francaise du Pétrole. 3(4): 95-103. gs


Rotalipora cushmani var. evoluta compiled by the pforams@mikrotax project team viewed: 2-3-2021

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Short stable page link: https://mikrotax.org/pforams/index.php?id=110494 Go to Archive.is to create a permanent copy of this page - citation notes

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