pforams@mikrotax - Conoglobigerina pforams@mikrotax - Conoglobigerina

Conoglobigerina


Classification: pf_mesozoic -> Conoglobigerinidae -> Conoglobigerina
Sister taxa: Conoglobigerina, Globuligerina, Petaloglobigerina
Daughter taxa (time control age-window is: 0-800Ma)
Conoglobigerina caucasica

Conoglobigerina grigelisi

Conoglobigerina gulekhensis

Conoglobigerina helvetojurassica

Conoglobigerina sp.
Specimens which cannot be assigned to established species

Taxonomy

Citation: Conoglobigerina Morozova 1961
taxonomic rank: Genus
Type species: Globigerina (Conoglobigerina) dagestanica Morozova, in Morozova and Moskalenko, 1961;
Taxonomic discussion: The taxonomic concpets of this genus has varied. Morozova and Moskalenko (1961) used it for species with test diameter < test height. Simmons et al. (1997) used it for forms with an intraumbilical, interiomarginal and low arch aperture. Gradstein et al. (2017) used it for froms with an irregularly reticulate wall surface pattern. This has resulted in the species assigned to the genus changing. See Gradstein et al. (2017) for full discussion.

Original description: Translation from the Russian - Test with a high spiral, height usually equal to or greater than the diameter (H:D > 1:1). The spiral is formed by three or four whorls less frequently by 2 or 2½ whorls. Chambers subspherical, more or less losely aranged. The number of chambers is inconstant, and varies from three to six per whorl. Fre:quently, there there are specimens with a multichambered initial whorl consisting of 5 or 6 chambers, the subsequent wholrs comprising 3 or 4 chambers each; however some forms have an equal numbers of chambers in all whorls. in some representatives of the subgenus the chambers are arranged so as to form more or less regular rows; in others, no regular pattern in the arrangement of chambers is noticeable. Aperture small, single. Wall thin, finely porous, surface smooth or slightly rugose. Family Globigerinidae. Middle Jurassic-Recent(?).

Entries in the Catalog of original descriptions: Conoglobigerina

Distinguishing features:
Parent taxon (Conoglobigerinidae): Small (<200µm), microperforate wall, 3-4 globose chambers in final wall, aperture umbilical
This taxon: Chambers of the last whorl strongly embrace previous whorls; irregularly reticulate wall surface pattern


Morphology:

Test trochospiral, low to medium high spired (H/D ratio 0.5–1, rarely over 1); final whorl may be compact or more open in shape. Chamber shape globular, rounded, rarely slightly irregular with 3.5–4 chambers in last whorl. Chambers of the last whorl strongly embrace previous whorls. Apertural shape variable, low arch or slit; mostly umbilical, but may be slightly extraumbilical in position. Wall microperforate, with small or larger, blunt pustules; pustules fuse to form ridges that are organized in broken cells that form an imperfect reticulate pattern. [Gradstein et al 2017]

Character matrix
test outline:Lobatechamber arrangement:Trochospiraledge view:Spiroconvexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Low-moderateperiphery:N/Aaperture border:
umb chbr shape:Globularumbilicus:periph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:wall texture:Finely pustuloseshell porosity:Microperforate: <1µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:0-0 N.B. These characters are used for advanced search. N/A - not applicable

Most likely ancestor: Globuligerina - at confidence level 2 (out of 5). Data source: Gradstein et al. (2017) p. 263.

Geological Range:
Last occurrence (top): at top of Valanginian Stage (100% up, 132.6Ma, in Hauterivian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within Middle Oxfordian Substage (156.60-159.40Ma, base in Oxfordian stage). Data source: Total of ranges of species in this database

Plot of range and occurrence data:

References:

Gradstein, F. M., Gale, A. S., Kopaevich, L., Waskowska, A., Grigelis, A. & Glinskikh, L. (2017b). The planktonic foraminifera of the Jurassic. Part I: material and taxonomy. Swiss Journal of Palaeontology. 136(2): 187-257. gs O

Loeblich, A. R. & Tappan, H. (1988). Foraminiferal Genera and Their Classification (Volume I-II). Van Nostrand Reinhold Co., New York. 1-1059. gs

Morozova, V. G. & Moskalenko, T. A. (1961). Планктонные фораминиферы пограничных отложений байосского и батского ярусов Центрального Дагестана (Северо-Восточный Кавказ) [Foraminiferes planctoniques des depots limitrophes du Bajocien et du Bathonien du Daghestan central (Nord-Est du Caucase)]. Voprosyi Mikropaleontologii. 5: 3-30. gs

Simmons, M. D., Boudagher-Fadel, M. K., Banner, F. T. & Whittaker, J. E. (1997). The Jurassic Favusellacea, the earliest Globigerina. In, Boudagher-Fadel, M. K., Banner, F. T. & Whittaker, J. E. (eds) The Early Evolutionary History of Planktonic Foraminifera. British Micropalaeontological Society Publication Series . 17-30. gs


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Conoglobigerina compiled by the pforams@mikrotax project team viewed: 13-10-2024

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