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Rotalipora montsalvensis


Classification: pf_mesozoic -> Rotaliporidae -> Rotalipora -> Rotalipora montsalvensis
Sister taxa: R. cushmani, R. montsalvensis, R. praemontsalvensis, R. sp.

Taxonomy

Citation: Rotalipora montsalvensis (Mornod, 1950)
Rank: Species
Basionym: Globotruncana (Rotalipora) montsalvensis
Synonyms:

Type images:

Original description: Translated from French: [Biconvex shell, with a trochospiral, dextral mode of coiling, outline very lobate. Spiral side with three whorls, six square-shaped chambers in the last whorl; rapid increase in size from the first to the last whorl, weakly marked in this last whorl and even declining in the last chamber; chambers surface granulose inflated compared to the depressed sutures. In addition, a depressed area is present along the external edge of the first whorls. Sutural ridges poorly salient or absent, sutures and sutural ridges weakly arched or straight, meeting perpendicularly or even at a blunt angle the preceding whorl. The sutural ridge is in continuity with the carinal ridge forming between them an almost right angle. The umbilical side displays strongly inflated chambers, radially elongate, spatulate or shaped like stubby fingers; umbilical area very wide and deep. Sutural depressions well marked, straight, not all of them directed toward the center of the umbilicus, devoid of ridges. Nevertheless, presence of a small fold of the wall (instead of a sutural ridge) starting from the sutural aperture which probably corresponds to the lip that ornaments the veiled interiomarginal aperture. Small granular and sinuous lines between the sutural apertures. The chambers extend into calcareous decks which completely seal the umbilicus. The periphery is provided with a single barely distinct carinal ridge. Apertures characteristic of the genus: aperture interiomarginal, big and high, visible in the last chamber, capped by a small lip; sutural aperture located at the third of the sutural line, clearly visible in the chambers of the last whorl, large, semicircular, capped by a small lip. In the first chamber, this sutural aperture may split into two.]

Coquille biconvexe, à enroulement trochospiral dextrogyre, contour très lobé. Face spirale à 3 tours, 6 loges au dernier tour et à forme quadratique; accroissement rapide de la spire au passage des premiers au dernier tour, peu marqué dans celui-ci et même déprimé à la hauteur de la dernière loge; surface des loges à granules, renflée par rapport aux sutures déprimées. Une dépression suit en plus le bord externe des premiers tours. Bourrelets suturaux peu saillants ou absents, faiblement arqués vers l'avant ou droits ainsi que les sutures, tombant perpendiculairement ou même en angle obtus sur le tour antérieur. Le bourrelet suturai se poursuit par le bourrelet carénai en dessinant un angle presque droit. La face ombilicale offre des loges fortement renflées, allongées radialement en forme de spatules ou de doigts trapus; aire ombilicale très vaste et profonde. Dépressions suturales accusées, droites, ne se dirigeant pas toutes vers le centre de l'ombilic, dépourvues de bourrelets. Toutefois, à partir de l'ouverture suturale, un petit ourlet tient lieu de bourrelet suturai et doit correspondre à la lèvre qui orne l'ouverture intériomarginale voilée. De petits filets granuleux et sinueux courent entre les ouvertures suturales. Les loges se prolongent par des ponts calcaires qui ferment totalement l'ombilic. La périphérie est ornée d'un unique bourrelet carénai estompé. Ouvertures typiques du genre: ouverture intériomarginale grande et haute, visible dans la dernière loge, surmontée d'une petite lèvre; ouverture suturale située au 1:1 du parcours de la ligne suturale, très apparente dans les loges du dernier tour, large, semi-circulaire, surmontée d'une petite lèvre. A l'arrière de la première loge, elle peut se dédoubler.

Entries in the Catalog of original descriptions: Globotruncana (Rotalipora) montsalvensis, Globotruncana (Rotalipora) montsalvensis minor, Rotalipora turonica thomei

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:Lobatechamber arrangement:Trochospiraledge view:-aperture:-
sp chamber shape:Petaloidcoiling axis:Low-moderateperiphery:Single keelaperture border:Thin lip
umb chbr shape:Trapezoidalumbilicus:Wideperiph margin shape:Subangularaccessory apertures:-
spiral sutures:Raised beadedumb depth:Shallowwall texture:Finely pustuloseshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:5.5-6.5 N.B. These characters are used for advanced search. N/A - not applicable

References:

Mornod, L. (1950). Les Globorotalides du Cretace superieur du Montsalvens (Prealpes fribourgeoises). Eclogae Geologicae Helvetiae. 42(2): 573-595. gs V O


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Rotalipora montsalvensis compiled by the pforams@mikrotax project team viewed: 25-11-2020

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Short stable page link: http://mikrotax.org/pforams/index.php?id=110495 Go to Archive.is to create a permanent copy of this page - citation notes



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