Globorotaloides

NB TAXA WHICH ORIGINATE IN THE OLIGOCENE ARE NOT INCLUDED YET
Classification: pf_neogene -> Globorotalidae -> Globorotaloides
Sister taxa: Berggrenia, Dentigloborotalia, Dentoglobigerina, Globoconella, Globoquadrina, Globorotalia, Globorotaloides, Neogloboquadrina, Pulleniatina,

Distinguishing features: Trochospiral test, ovate to spherical chambers; final chamber often small/bulla-like; cancellate wall

Daughter taxa: (blue => in age window 0-300Ma)
Very low trochospiral, spiral side almost flat, equatorial periphery lobulate, chambers spherical
Test low trochospiral, lobulate, axial periphery rounded; 4 to 5 chambers in final whorl; aperture a low arch, often covered by bulla-like final chamber.
Like G. suteri but with more compressed early chambers, more curved sutures, and more (5-6 vs 4-5) chambers in the final whorl.
Specimens which cannot be assigned to established species

Taxonomy

Citation: Globorotaloides Bolli 1957
Rank: genus
Type species: Globorotaloides variabilis Bolli 1957
Taxonomic discussion: The genus Globorotaloides combines at various stages in its growth characteristic features of at least four generic forms. The first stage, with a distinct interiomarginal, umbilical-extraumbilical aperture, resembles "Globorotalia, "followed by a Globigerina-like stage where the aperture becomes umbilical. The presence of a bulla-like final chamber, covering part of or the entire umbilical area, is a Catapsydrax-like stage. Finally, the pitted nonspinose surface ultrastructure and the apertural plates of the adult test suggest relationships with Globoquadrina. For these reasons, species assigned here to Globorotaloides (Gd. suteri, Gd. variabilis, and Gd. hexagona) have variously been included in all of the above genera by different authors. [Kennett & Srinivasan 1983]

Catalog entries: Globorotaloides;

Type images:

Distinguishing features: Trochospiral test, ovate to spherical chambers; final chamber often small/bulla-like; cancellate wall

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


Diagnostic characters: The genus Globorotaloides includes forms with a trochospiral test, ovate to spherical chambers, a final chamber that is often smaller than the penultimate and may cover part of or the entire umbilicus and appear almost indistinguishable from a bulla; a distinctly cancellate surface; and a primary aperture, which in the early stage is interiomarginal, umbilical-extraumbilical, later becoming umbilical. [Kennett & Srinivasan 1983]

Biogeography and Palaeobiology


Phylogenetic relations: Globorotaloides is one of the long-ranging genera of the Cenozoic. The earliest member, Globorotaloides suteri, appeared during the Late Eocene. In the Neogene, the genus is represented by the Gd. suteri-Gd. variabilis-Gd. hexagona lineage (Text Fig. 24), although this is one of the least understood Neogene planktonic foraminiferal lineages. [Kennett & Srinivasan 1983]

Biostratigraphic distribution

Geological Range:
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): at base of Ypresian Stage (0% up, 56Ma, in Ypresian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Kennett & Srinivasan 1983, p.213

References:

Bolli, H.M., (1957). Planktonic foraminifera from the Oligocene-Miocene Cipero and Lengua formations of Trinidad, B.W.I. In: Loeblich, A.R., Jr. et al. (Editors), Studies in Foraminifera: U.S. National Museum Bulletin 215. U.S. Government Printing Office, Washington, DC, pp. 97-123.

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


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

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