Globigerinoides

NB TAXA WHICH ORIGINATE IN THE OLIGOCENE ARE NOT INCLUDED YET
Classification: pf_neogene -> Globigerinidae -> Globigerinoides
Sister taxa: Beella, Globigerina, Globigerinella, Protentella, Globigerinoides, Globigerinoidesella, Globoturborotalita, Orbulina, Praeorbulina, Sphaeroidinella, Sphaeroidinellopsis, Trilobatus, Turborotalita, Catapsydrax, Clavatorella, Paragloborotalia, Orcadia,

Distinguishing features: Supplementary apertures, with bulloides-type spinose wall texture

Daughter taxa: (blue => in age window 0-300Ma)
altiaperturus-obliquus-conglobatus lineage
Large, arched primary aperture and almost equally large supplementary aperture opposite it.
Tightly coiled test with flattened chambers and very small umbilicus
Strongly obliquely compressed & flattened final chamber.
Obliquely compressed final chamber.
subquadratus-ruber lineage
Like Gs. ruber but chambers radially compressed
3 subspherical chambers in final whorl; primary and supplementary apertures, symmetrically placed above a suture.
Large test with very high spire, and large, asymmetric primary aperture
Like G. ruber but somewhat aberrant primary aperture and large supplementary apertures
Like G. ruber but subquadrate. Prominent supplementary apertures
Like G. subquadratus but very small, compact test. Apertures almost curcular, symmetrically above sutures.
others
Like G. bulloides but with supplementary apertures on the spiral side
Like G. altiapertura but smaller with smaller primary aperture, and single small supplementary aperture
Specimens which cannot be assigned to established species

Taxonomy

Citation: Globigerinoides Cushman 1927
Rank: genus
Type species: Globigerina rubra d'Orbigny 1839
Taxonomic discussion: The genus Globigerinoides was used by Kennett & Srinivasan (1983) and many other workers for all Neogene  Globigerina-type species with supplementary apertures, but it was long suspected that this was a polyphyletic group. Spezzaferri et al. (2015) conclusively proved this polyphyly using both stratophentic and molecular genetic data and so divided the species into two groups - Trilobatus and Globigerinoides, as used here. They have separate origins and different wall structures.

Catalog entries: Globigerinoides;

Type images:

Distinguishing features: Supplementary apertures, with bulloides-type spinose wall texture

NB The short diagnoses are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They have initially been copied from the diagnostic characters/distinguishing features sections of the Eocene and Paleocene Atlases, they will be edited as the site is developed.

Description


Wall type: The wall texture is cancellate, irregular honeycomb, with spines irregularly distributed, it may be ruber-type or sacculifer/ruber-type sensu Hemleben et al. 1989. [Spezzaferri et al. 2015]

Test morphology:

Test low to high trochospiral, globigeriniform and generally evolute, consisting of 2½ to 3 whorls. The peripheral margin is rounded, the test outline is from subcircular to slightly ovate or subtriangular to subrectangular and lobate. Chambers are generally globular to ovate, but may become radially compressed and asymmetrical, three to four in the last whorl increasing gradually in size as added. The primary aperture is umbilical and placed in a generally wide and open umbilical area; supplementary apertures are present on the spiral side, they may be one or more and are placed at the intersection of the spiral and radial sutures. Thin lips may be present on the primary and supplementary apertures. [Spezzaferri et al. 2015]

Biogeography and Palaeobiology

See also: Trilobatus - sacculifer and several other species are now placed in this genus.;

Biostratigraphic distribution

Geological Range:
Notes: The genus first appears at the Oligocene-Miocene transition, and in particular at the base of Subzone M1a and is still present in the modern oceans. [Spezzaferri et al. 2015]
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): near top of Chattian Stage (91% up, 23.5Ma, in Chattian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Spezzaferri et al. 2015

References:

Cushman, J.A., (1927). An outline of a re-classification of the Foraminifera. Contributions from the Cushman Laboratory for Foraminiferal Research, 3: 1-105.

Hemleben, C.; Spindler, M. & Anderson, O., (1989). Modern Planktonic Foraminifera. Springer-Verlag, New York.

Kennett, J.P. & Srinivasan, M.S., (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania, 1-265 pp.

Spezzaferri, S. & others, (2015). Fossil and genetic evidence for the polyphyletic nature of the planktonic foraminifera "Globigerinoides", and description of the new genus Trilobatus. PLOS one: 1-20.


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Globigerinoides compiled by the pforams@mikrotax project team viewed: 16-8-2018

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