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Costellagerina pilula


Classification: pf_mesozoic -> Hedbergellidae -> Costellagerina -> Costellagerina pilula
Sister taxa: C. bulbosa, C. pilula,

Taxonomy

Citation: Costellagerina pilula (Belford, 1960)
Rank: Species
Basionym: Rugoglobigerina pilula
Synonyms: Rugoglobigerina (Rugoglobigerina) plana

Type images:

Original description: Rugoglobigerina pilula Belford 1960: Test trochoid, both dextrally and sinistrally coiledforms known, with the latter the more common; umbilicus small, circular, usually infilled. Test trochoid, both dextrally and sinistrally coiled forms occurring, with the latter the more common; umbilicus small, circular, usually infilled. chambers globular, strongly inflated, forming two and one-half to three whorls, each whorl only partly overlapping the one preceding, forming a high sire; five or six chambers in last whorl, increasing slowly in size as added. Sutures straight or slightly curved on spiral side, straight on umbilical side, depressed on both sides. Test ornamented with small discontinuous ridges, irregularly arranged on early chambers and forming a meridional pattern on chambers of last whorl, the last one or two chambers may be smooth. Wall of test calcareous, finely perforate, radiate in structure. Aperture interiomarginal umbilical, large and arcuate, not often observed because of infilling umbilicus; only remnants of tegilla have been observed.

Entries in the Catalog of original descriptions: Rugoglobigerina (Rugoglobigerina) plana;
Rugoglobigerina pilula;

Geological Range:
Last occurrence (top): within G. elevata zone (79.20-84.19Ma, top in Campanian stage). Data source: [copied from Chronos database]
First occurrence (base): within D. asymetrica zone (84.19-86.71Ma, base in Coniacian stage). Data source: [copied from Chronos database]

Plot of occurrence data:

NB Plotting of Neptune data has been disabled on the Mesozoic pages because the dataset is both small and badly affected by a few sites with erroneous age models (our obs Huber, Petrizzo, Young, Nov 2016). The data can still be viewed via the range plottertool - tools menu.

Character matrix

test outline:Subcircularcoiling axis:Highchamber arrangement:Trochospiralumbilicus:Wide
edge view:Concavo-convexumbilical or test sutures:Strongly depressedspiral sutures:Strongly depressedshell porosity:
wall texture:Meridional costellaeaperture:Interiomarginalaperture border:accessory apertures:None
periphery:umb chamber shape:Inflatedsp chbr shape:Inflatedperiph margin shape:Broadly rounded
umb depth:Deepdiameter mm:0.33 mm to 0.36 mmwidth mm:0.21 to 0.23breadth mm:
final-whorl chambers:5.0-6.0

References:

Belford, D.J., (1960). Upper Cretaceous foraminifera from the Toolonga Calcilutite and Gingin Chalk, Western Australia. Australia Bureau of Mineral Resources, Geology and Geophysics Bulletin, 57: 1-198.


Costellagerina pilula compiled by the pforams@mikrotax project team viewed: 23-5-2017

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