nmn

Rotalipora praemontsalvensis


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

Taxonomy

Citation: Rotalipora praemontsalvensis Ion 1976
Rank: Species
Basionym: Rotalipora praemontsalvensis

Type images:

Original description: Translated from French: Species characterized by more or less globular chambers, an almost flat coiling with a tendency to become evolute (subspecies altispira), a test outline lobate to strongly lobate with clavate chambers (subspecies lobata); the marginal keel is incompletely developed. Description. The test of this species is an almost flat and nearly symmetrical trochospire, the consequence of a loose coiling of almost globular and regularly increasing in size chambers. The globular shape becomes clearer toward the periphery of the chambers and toward the last-formed chambers. Their outline is lobate to very lobate. The spiral side displays two and a half whorls, the last whorl comprising 5-7 chambers with the 2-3 first chambers almost rounded and the last chambers square and sometimes radially elongate-clavate; chambers surface almost globular, separated by slightly depressed, radial or slightly curved in a frontward direction sutures; The spiral suture separating the last whorl is very depressed. The umbilical side shows 5-7 square, globular, spatulate chambers separated by depressed sutures. The main aperture is interiomarginal-umbilical in position, narrow; the accessory or supplementary apertures are intrasutural, along the last and the last but one suture; the sutural apertures may split into two, they are broad and oval in shape, backward oriented except for the last aperture which may be frontward directed. On the spiral as well as on the umbilical sides, the chambers surface is generally smooth except for the margins of the first chambers of the last whorl which, sometimes, are very finely rugose. In the more evolved forms of praemontsalvensis the chamber ornamentation consists of a very thin keel along the periphery of the 1-3 first chambers of the last whorl and that of the last chambers of the preceding whorl. The periphery of the last-formed chamber is rounded or displays a 50 to 90° angular section.

Entries in the Catalog of original descriptions: Rotalipora praemontsalvensis

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:Spiroconvexaperture:Umbilical-extraumbilical
sp chamber shape:Petaloidcoiling axis:Low-moderateperiphery:Single keelaperture border:Thin flange
umb chbr shape:Subtriangularumbilicus:Wideperiph margin shape:Subangularaccessory apertures:Sutural
spiral sutures:Moderately depressedumb depth:Shallowwall texture:Smoothshell porosity:Microperforate: <1┬Ám
umbilical or test sutures:Strongly depressedfinal-whorl chambers:6.0-6.5 N.B. These characters are used for advanced search. N/A - not applicable

References:

Ion, J. (1976). A propos de la souche des Rotalipores. Rotalipora praemontsalvensis n. sp. Dari de Seama ale Sedintelor Institutul de Geologie si Geofizica 3 Paleontologie. 62(3): 39-45. gs


logo

Rotalipora praemontsalvensis compiled by the pforams@mikrotax project team viewed: 23-11-2020

Taxon Search:
Advanced Search

Short stable page link: http://mikrotax.org/pforams/index.php?id=110496 Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet on this page. Please do add comments if you spot any problems, or have information to share

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics