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Conoglobigerina caucasica


Classification: pf_mesozoic -> Conoglobigerinidae -> Conoglobigerina -> Conoglobigerina caucasica
Sister taxa: C. avarica, C. balakhmatovae, C. caucasica, C. conica, C. dagestanica, C. gulekhensis, C. jurassica, C. meganomica, C. terquemi, C. sp.,

Taxonomy

Citation: Conoglobigerina caucasica (Gorbachik & Poroshina, 1979)
Rank: Species
Basionym: Globuligerina caucasica
Taxonomic discussion: Surface of test under the binocular microscope appears smooth at X 96, when studied with the electron microscope (x 1000 and X 3000) a cancellate ornamentation is visible. Unfortunately, the specimens studied are not well enough preserved, the ornamentation being retained only in parts of the test and even there partly destroyed. Cells roughly quadrangular, separated by relatively broad, smooth ridges. The cells are 2-4 microns in size. Pores lie mainly within the cells, but single pores are observed on the ridges too. Pores round or oval, about 0.5 microns in size (tf. 3c, d). [copied from Chronos database]

Type images:

Original description: Globuligerina caucasica Gorbachik & Poroshina 1979: Translation from Russian: Test small, diameter no more than 0.23 mm, usually oval, concavo-convex, low trochoid, height about twice as small as the diameter. Coil made up of 2-2.5 whorls. Early chambers very small, weakly convex, oval or rounded in outline, hard to discern and only slightly surmounting the chambers of the last whorl. There are four or five of them. In the last whorl are four chambers, rapidly increasing in dimensions, relatively low, and somewhat flattend. Septal sutures depressed, slightly curved in the early chambers and nearly straight in the later ones. Peripheral margin narrow, rounded, outline of test distinctly lobate. Umbilicus small, narrow. Aperture opens into umbilicus and extends along the base of the last chambers, not reaching the peripheral margin, arcuate, fringed with a narrow, slightly expressed lip, filled with rock in the specimens studied. Wall finely perforate.

Entries in the Catalog of original descriptions: Globuligerina caucasica;

Geological Range:
Last occurrence (top): within Valanginian Stage (133.88-139.39Ma, top in Valanginian stage). Data source: [copied from Chronos database]
First occurrence (base): within Berriasian Stage (139.39-145.01Ma, base in Berriasian 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:Lobatechamber arrangement:Trochospiraledge view:Spiroconvexaperture:Umbilical
umb chamber shape:Globularcoiling axis:Low-moderateperiphery:N/Aaperture border:N/A
sp chbr shape:Globularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:N/A
umbilical or test sutures:Moderately depressedumb depth:Shallowwall texture:Reg. favolateshell porosity:
spiral sutures:Moderately depresseddiameter mm:0.2width mm:0.17breadth mm:0.1
final-whorl chambers:4.0-5.0

References:

Gorbachik, T.N. & Poroshina, L.A., (1979). Новые планктонные фораминиферы из берриасских отложений Азербайджана [New planktonic foraminifera from the Berriasian of Azerbaijan]. Paleontological Journal, 3: 22-28.


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Conoglobigerina caucasica compiled by the pforams@mikrotax project team viewed: 17-12-2017

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