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Conoglobigerina gulekhensis


Classification: pf_mesozoic -> Conoglobigerinidae -> Conoglobigerina -> Conoglobigerina gulekhensis
Sister taxa: C. caucasica, C. grigelisi, C. gulekhensis, C. helvetojurassica, C. sp.

Taxonomy

Citation: Conoglobigerina gulekhensis (Gorbachik & Poroshina, 1979)
Rank: Species
Basionym: Globuligerina gulekhensis

Type images:

Original description: Test small, diameter no more than 0.25 mm, high-trochoid; test outline subquadrate, sharply lobate. The coil making up the initial whorls is somewhat off-center relative to the last whorl and sharply demarcated from its surface. Peripheral margin broad, rounded. Test consists of 12-13 chambers, forming 2½-3 whorls. Chambers of initial whorls spherical or ellipsoidal, closely appressed. In the last whorl there are four subspherical chambers, more freely arranged. Dimensions of chambers in each whorl increase gradually; the chambers of the early whorls differ markedly in size. Septal sutures depressed straight. Umbilicus shallow, narrow. Aperture opens into umbilicus, arcuate, has a barely noticeable lip. Test wall finely perforate, surface appears smooth under a binocular microscope at x96, when studied with the electron microscope (x1000 and x3000) a clearly expressed cancellate structure is visible. The cells are roughly rectangular, divided by broad, high, smoothed-off ridges. Cells reach 2 µm in size. Pores round or oval, located mainly inside the cells, there are single pores on the ridges as well. There are two orders of pores - small, around 0.33 µm in size; and large - up to 1 µm. Small pores predominate.

Entries in the Catalog of original descriptions: Globuligerina gulekhensis

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): at base of C. gulekhensis zone (0% up, 146Ma, in Tithonian stage). Data source: zonal marker (from Timescale Creator)

Plot of range and occurrence data:

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Spiroconvexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Moderate-highperiphery:N/Aaperture border:Thin lip
umb chbr shape:Globularumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:Shallowwall texture:Finely pustuloseshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:4.0-4.0 N.B. These characters are used for advanced search. N/A - not applicable

References:

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


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Conoglobigerina gulekhensis compiled by the pforams@mikrotax project team viewed: 22-1-2021

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Short stable page link: http://mikrotax.org/pforams/index.php?id=110061 Go to Archive.is to create a permanent copy of this page - citation notes



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