CATALOG OF ORIGINAL DESCRIPTIONS: Globigerinoides obliquus extremus Bolli & Bermudez 1965

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.

Higher levels: pf_cat -> G -> Globigerinoides -> Globigerinoides obliquus extremus
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Globigerinoides obliquus extremus

Citation: Globigerinoides obliquus extremus Bolli & Bermudez 1965
Rank: sub-species
Type locality: Isla Cubagua, Estado Nueva Esparta, Venezuela
Type age (chronostrat): Globorotalia margaritae Zone,
Type sample (& lithostrat): core 1029-1034 feet of well Cubagua-1; Cubagua formation
Type specimens: Plate 1, Figures 10 - 12
Type repository: USNM
Described on page(s) : 139

Linked specimens: USNM-642538

Current identification/main database link: Globigerinoides extremus Bolli & Bermudez 1965

Original Description
Shape of test high trochospiral; equatorial periphery distinctly lobate; axial periphery rounded. Wall calcareous, perforate, surface finely pitted. Chambers of the last whorl progressively more compressed in a lateral, oblique manner; 10 - 12, arranged in 2 to 3 whorls; the 4 chambers of the last whorl increase fairly rapidly in size, though the last chamber may be slightly re- duced in some specimens. Sutures somewhat oblique on spiral and umbilical side, incised. Umbilicus rather narrow. Primary aperture a distinct arch of medium height, interiomarginal, umbilical. One supplementary aperture on last chamber often also visible on earlier ones.

Size: Largest diameter of holotype: 0.36 mm.

Extra details from original publication
Remarks: Globigerinoides obliquus extremus evolved from Globigerinoides obliquus obliquus Bolli 1957,p.113) probably in the Globorotalia acostaensis zone. It differs from Globigerinoides obliquus obliquus in that even the earlier chambers of the last whorl are compressed in a laterally oblique manner, and the compression of the final chamber is much more pronnounced than in the type subspecies. The new subspecies continues to or near the top of the Miocene. It is no longer present in the Pliocene Cumana and Playa Grande formations of coastal northeastern Venezuela and is also not known from the Recent. Its characteristically compressed chambers and its range restricted to the uppermost Middle and the Upper Miocene make the subspecies a good index fossil. In the well section of Bodjonegoro-1, Java, it has been found in a similar stratigraphic position. The subspecies has been chosen as a comarker for the Globorotalia dutertrei/Globigerinoides obliquus extremus Zone which is defined in this paper.

Stratigraphic range: Globorotalia acostaensis Zone to Globoquadrina altispira altispira/Globorotalia crassaformis Zone, Middle Miocene to Upper Miocene, Cubagua formation, Venezuela.


Bolli, H. M. & Bermudez, P. J. (1965). Zonation based on planktonic foraminifera of middle Miocene to Pliocene warm-water sediments. Bol. Informativo, Asoc. Venez. Geol., Min. Petrol. 8(5): 121-149. gs


Globigerinoides obliquus extremus compiled by the pforams@mikrotax project team viewed: 21-4-2021

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