Globoquadrina

NB TAXA WHICH ORIGINATE IN THE OLIGOCENE ARE NOT INCLUDED YET
Classification: pf_neogene -> Globorotalidae -> Globoquadrina
Sister taxa: Berggrenia, Dentigloborotalia, Dentoglobigerina, Globoconella, Globoquadrina, Globorotalia, Globorotaloides, Neogloboquadrina, Pulleniatina,
Daughter taxa (blue => in age window 0-300Ma)


Specimens which cannot be assigned to established species

Taxonomy

Citation: Globoquadrina Finlay 1947
Rank: genus
Type species: Globorotalia dehiscens
Taxonomic discussion: Globoquadrina as defined includes trochospiral forms with quadrate to subquadrate equatorial profile and an aperture in interiomarginal, umbilical-extraumbilical position, with one or more tooth-like projections extending into the umbilicus. Parker (1962, 1967) placed all living species with nonspinose, pitted wall structure in Globoquadrina such as hexagona, dutertrei, and others, irrespective of their phylogenetic relationship. Fleisher (1974) distinguished five distinct lineages within Globoquadrina, each charasterized by distinct but minor morphologic features, and suggested that these may be separated at the subgeneric level. Blow (1979) proposed Dentoglobigerina for morphotypes possessing an umbilical tooth over an umbilically restricted aperture. These forms are placed in Globoquadrina by most workers. This genus was distinguished from Globoquadrina by its umbilically restricted aperture and from Globigerina by the presence of umbilical teeth.

In the present study we adopt Dentoglobigerina only for the evolutionary lineage that extends from D. galavisi to D. globularis to D. altispira globosa to D. altispira altispira. The generic name Dentoglobigerina cannot be used for Gq. venezuelana, Gq. tripartita/sellii, Gq. binaiensis, and Gq. praedehiscens morphotypes as suggested in the restricted morphological sense by Blow (1979) and adopted by Chaproniere (1981) because these forms are phyletically unrelated to the D. galavisi-D. altispira altispira lineage.

On the contrary, Gq. tripartita selli-Gq. binaiensis-Gq. praedehiscens-Gq. dehiscens represent one continuous evolutionary lineage showing a gradual morphological change from an umbilically restricted aperture to an umbilical-extraumbilical aperture (Text Fig. 20). Splitting of this continuous phyletic series into two separate genera Dentoglobigerina (for forms with an umbilically restricted aperture) and Globoquadrina (for forms with an umbilical-extraumbilical aperture), is nonphylogenetic and hence artificial. Thus, within a phylogenetic concept, we restrict Dentoglobigerina Blow to the D. galavisi to D. altispira lineage and use Globoquadrina for the Gq. tripartita/selli-Gq. binaiensis-Gq. praedehiscens-Gq. dehiscens lineage (Text Fig. 20).

Catalog entries: Globoquadrina;

Type images:

Short diagnosis: trochospiral with quadrate to subquadrate profile; aperture in interiomarginal / umbilical-extraumbilical, one or more tooth-like projections extending into the umbilicus.

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

Biogeography and Palaeobiology


Phylogenetic relations: The ancestry of Gq. venezuelana is unknown. Speculations are that it is probably related to Gq. tripartita (Fleisher, 1974) or the Subbotina linaperta group (Stainforth, 1974), but it is certainly unrelated to the D. galavisi to D. altispira lineage.
For this reason venezuelana is provisionally assigned to Globoquadrina.

Biostratigraphic distribution

Geological Range:
Notes: Both Dentoglobigerina and Globoquadrina evolved in the latest Oligocene and are largely confined to the Miocene.
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): within Aquitanian Stage (20.44-23.03Ma, base in Aquitanian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Kennett & Srinivisan 1983, p.178

References:

Finlay, H.J., (1947). New Zealand foraminifera: Key species in stratigraphy - no. 5. New Zealand Journal of Science and Technology, 28(5): 259-292.


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Globoquadrina compiled by the pforams@mikrotax project team viewed: 24-2-2018

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