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DSDP Site 463-465-289.JPGTaxonomy
Not in Ellis and Messina for some reason, but Todd Library has Sigals reprint. [copied from Chronos database]
holotype: R. cushmani evolutaOriginal 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: | Ovate | chamber arrangement: | Trochospiral | edge view: | Compressed | aperture: | - |
| sp chamber shape: | Petaloid | coiling axis: | Low | periphery: | Single keel | aperture border: | Thin lip |
| umb chbr shape: | Subtriangular | umbilicus: | Narrow | periph margin shape: | Subangular | accessory apertures: | Sutural |
| spiral sutures: | Raised beaded | umb depth: | Shallow | wall texture: | Finely pustulose | shell porosity: | Finely Perforate: 1-2.5µm |
| umbilical or test sutures: | Moderately depressed | final-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. gsReferences:
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Rotalipora cushmani var. evoluta compiled by the pforams@mikrotax project team viewed: 2-3-2021
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 |