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Gorbachikella depressa


Classification: pf_mesozoic -> Praehedbergellidae -> Gorbachikella -> Gorbachikella depressa
Sister taxa: G. depressa, G. grandiapertura, G. kugleri, G. neilii, G. sp.,

Taxonomy

Citation: Gorbachikella depressa Boudagher-Fadel, Banner, Brown, Simmons, Gorbachil, 1995
Rank: Species
Basionym: Gorbachikella depressa
Taxonomic discussion: Gorbachikella depressa differs from the other gorbachikellids in having a lower-arched aperture, a smaller umbilical area and, possibly, an irregular growth rate. [copied from Chronos database]

Type images:

Original description: Gorbachikella depressa differs from G. kugleri in having a more depressed periphery of each chamber, a very low symmetrical axiointraumbilical aperture with a very weak rim, and a higher spire. The aperture is similar to the Conoglobigerina- type aperture, but the surface of the test is smooth and microperforate (see Pl. 3 , fig. 3b, 4b).

Entries in the Catalog of original descriptions: Gorbachikella depressa


Emended description: Test small to medium, trochospirally coiled, globigeriniform; 4 chambers in the outer whorl; chambers globular to subglobular increasing rather slowly and gradually in size as added; some individuals grow rather irregularly exhibiting an extremely developed second chamber and an ultimate chamber smaller than the penultimate one; sutures depressed and radial; peripheral outline round and lobate; umbilicus rather small and shallow; dorsal side slightly to strongly convex; aperture umbilical as a low arch, possibly bordered by a narrow imperforate lip; wall calcareous, finely perforate, pores diameter usually comprised between 1 and 2mm; perforations unevenly distributed, widely-spaced and badly-defined in shape. [copied from Chronos database]

Geological Range:
Last occurrence (top): within Aptian Stage (112.95-126.30Ma, top in Aptian stage). Data source: [copied from Chronos database]
First occurrence (base): within Hauterivian Stage (130.77-133.88Ma, base in Hauterivian 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

  • (NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Gorbachikella

    Character matrix

    test outline:Lobatechamber arrangement:Trochospiraledge view:Spiroconvexaperture:Umbilical
    sp chamber shape:Inflatedcoiling axis:Moderateperiphery:N/Aaperture border:Thin lip
    umb chbr shape:Inflatedumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
    spiral sutures:Moderately depressedumb depth:Shallowwall texture:Smoothshell 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:

    BouDagher-Fadel, M., Banner, F. T., Bown, P. R., Simmons, M. D. & Gorbachik, T. N. (1995). Gorbachikella from the Hauterivian, Barremian-Aptian of Tunisia. Revue de Micropaléontologie. 38(3): 179-193. gs


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    Gorbachikella depressa compiled by the pforams@mikrotax project team viewed: 15-11-2019

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    Short stable page link: http://mikrotax.org/pforams/index.php?id=110206 Go to Archive.is to create a permanent copy of this page - citation notes



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