Kennett & Srinivasan (1983):
Gs. primordius differs from its immediate ancestor Globigerina (Gg.)praebulloides by the single, small, supplementary aperture on its spiral side. It develops into Gs. altiapertura Bolli, which is distinguished by its larger, high-arched primary and supplementary apertures.
Bolli & Saunders (1985):
This species is the immediate ancestor of the Globigerinoides trilobus stock, with overall morphological features already very close, in particular to G. trilobus immaturus. Typical primordius specimens differ in having more delicately built chamber walls, in the primary aperture being higher arched and in possessing only a single secondary opening, situated on the spiral side of the last chamber. It is generally agreed that the immediate ancestor of this first Globigerinoides species is a Globigerina. According to Blow & Banner it is very close to G. praebulloides occlusa (Fig. 13.12) from which it differs primarily only in the presence of a spiral secondary aperture. The confusion caused by the lectotype of Globigerinoides 'quadrilobatus' erected by Banner & Blow is discussed in the taxonomic notes of the Globigerinoides trilobus group. The difficulty of using the first occurrence of G. primordius to delineate the Oligocene Miocene boundary is discussed on p. 191.
Spezzaferri & Silva (1990):
Typical forms are preceded in
Zone P21 by specimens displaying the same shape
and wall structure as G. primordius without supplementary
apertures. The latter are plotted under the
informal name of "Globigerinoides"praeprimordius
(Plate VIII, 2a-c).
Chaisson & Leckie (1993):
Similar species: The surface texture of Globigerinoides primordius resembles
its ancestor Globigerina praebulloides in being smoother and less
coarsely cancellate than Globigerinoides triloba. G. primordius also differs
from early forms of G. triloba in having higher arched apertures, although not
as high as G. altiapertura. |
Blow,W.H. and Banner,F.T. (1962):
The Mid-Tertiary (Upper Eocene to Aquitanian) Globigerinaceae.
In: Fundamentals of Mid‑Tertiary Stratigraphical Correlation Eds: Eames, F.E.Banner, F.T.Blow, W.H.Clarke, W.J. p. 61‑151
Kennett,J. and Srinivasan,M.S. (1983):
Neogene Planktonic Foraminifera - A Phylogenetic Atlas.
Bolli,H.M. and Saunders,J.B. (1985):
Oligocene to Holocene low latitude planktic foraminifers.
In: Plankton Stratigraphy Eds: Bolli, H.M.Saunders, J.B. p. 155-262
Spezzaferri,S. and Silva,I.S.. (1990):
Oligocene planktonic foraminiferal biostratigraphy and paleoclimatic interpretation from Hole 538A, DSDP Leg 77, Gulf of Mexico . Palaeogeography, Palaeoclimatology, Palaeoecology Vol. 83 p. 217-263
Vincent,E. and Toumarkine,M. (1990):
Neogene planktonic foraminifers from the Western Tropical Indian Ocean, Leg 115.
In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 115 Eds: Duncan, R.A..Backman, J.Peterson, L.C. p. 795-836
Chaisson,W.P. and Leckie,R.M. (1993):
High-Resolution Planktonic Foraminifer Biostratigraphy of Site 806, Ontong Java Plateau (Western Equatorial Pacific).
In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 130 Eds: Berger, W.H.Kroenke, L.W..Mayer, L.A..et al. p. 137-178
Berggren,W.A.; Kent,D.V.; Swisher,C.C. and Aubry,M.P. (1995):
A revised Cenozoic Geochronology and Chronostratigraphy.
In: Geochronology Time Scales and Global Stratigraphic Correlation, SEPM Special Publication Vol. 54
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