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Loeblichella coarctata


Classification: pf_mesozoic -> Globotruncanidae -> Loeblichella -> Loeblichella coarctata
Sister taxa: L. coarctata, L. convexa, L. hessi, L. sp.,

Taxonomy

Citation: Loeblichella coarctata (Bolli, 1957)
Rank: Species
Basionym: Praeglobotruncana coarctata

Type images:

Original description: Shape of test very low trochospiral, biconvex; equatorial periphery lobate; a faint keel is often observed in last chambers; it may be ornamented with minute spines on peripheral edge. Wall calcareous, perforate, surface smooth. Chambers strongly compressed, 10-12, arranged in 2 whorls; the 5-6 chambers of the last whorl increase rapidly in size; the early whorl minute by comparison. Sutures on spiral side radial or slightly curved, depressed; on umbilical side radial, depressed. At umbilicus each chamber of last whorl extends towards the center, leaving only a small portion open. Aperture a low arched, interiomarginal, extraumbilical-umbilical slit. Coiling predominantly dextral; of 37 specimens counted only 4 coiled sinistrally.

Entries in the Catalog of original descriptions: Praeglobotruncana coarctata

Geological Range:
Last occurrence (top): within R. calcarata zone (75.71-76.18Ma, top in Campanian stage). Data source: [copied from Chronos database]
First occurrence (base): within G. ventricosa zone (76.18-79.20Ma, base in Campanian stage). Data source: [copied from Chronos database]

Plot of occurrence data:

Dec 2017 - Plotting of Neptune data has been re-enabled on the Mesozoic pages following revision of the age-models in Neptune. The data is, however, still very sparse for the Early Cretaceous

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Extraumbilical-peripheral
sp chamber shape:Inflatedcoiling axis:Very lowperiphery:Single keelaperture border:Thin lip
umb chbr shape:Inflatedumbilicus:Wideperiph margin shape:Moderately roundedaccessory apertures:Relict
spiral sutures:Strongly depressedumb depth:Shallowwall texture:Smoothshell porosity:
umbilical or test sutures:Strongly depressedfinal-whorl chambers:5.0-6.0 N.B. These characters are used for advanced search. N/A - not applicable

References:

Bolli, H. M. (1957e). The genera Praeglobotruncana, Rotalipora, Globotruncana, and Abathomphalus in the Upper Cretaceous of Trinidad, B. W. I. In, Loeblich, A. R. , Jr. , Tappan, H. , Beckmann, J. P. , Bolli, H. M. , Montanaro Gallitelli, E. & Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin. 215: 51-60. gs V O

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


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Loeblichella coarctata compiled by the pforams@mikrotax project team viewed: 25-9-2020

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Short stable page link: http://mikrotax.org/pforams/index.php?id=110321 Go to Archive.is to create a permanent copy of this page - citation notes



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