CATALOG OF ORIGINAL DESCRIPTIONS: Globigerinoides subquadrata Brönnimann, in Todd et al. 1954

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 subquadrata
Other pages this level: << < G. rubra seigliei, G. rubriformis, G. sacculifer brachysacculifer, G. sacculifer minimus, G. sacculifer spinulosus, G. sacculifera subsacculifera, G. sacculiferoides, G. sacculiferus immatura, G. sacculiferus irregularis, G. semiinvoluta, G. semiinvolutus, G. sicanus, G. sicanus praesicanus, G. subconglobatus micra, G. subconglobatus subconglobata, G. subquadrata, G. subquadratus praesubquadratus, G. subquadratus subelongatus, G. suleki, G. tapiesi, G. tenella, G. transitoria, G. triloba altiapertura, G. triloba aspera, G. trilobus bullatus, G. tyrrhenicus

Globigerinoides subquadrata

Citation: Globigerinoides subquadrata Brönnimann, in Todd et al. 1954
Rank: species
Type locality: 1.6 miles northeast of the seaward tip of the southwest point of Saipan (Joe. C-85, fig. 2).
Type age (chronostrat): upper Oligocene
Type specimens: Plate 1, figures 5, 8; USNM-548881
Type repository: Washington; USNM

Linked specimens: USNM-623955 USNM-548880 USNM-548881

Current identification/main database link: Globigerinoides subquadratus Brönnimann, in Todd et al. 1954


Original Description
The general outline of the test is subquadrate. The major portion of the test is represented by the three-chambered final volution. The early portion of the test is distinctly trochoid. It is only slightly smaller than the antipenultimate chamber. The subglobular and appressed chambers of the final volution increase rapidly in size, and the end chamber is equal to or only slightly smaller than the preceding part of the test. The ultimate and penultimate chambers are added perpendicularly to the preceding oral face. The initial spiral is indistinct and the spiral side is much like the umbilical side. The umbilicus is very shallow. The arcuate main aperture is situated at the intersection of the umbilical sutures; the smaller. also arcuate. accessory aperture is opposite the main aperture on the spiral side. Additional accessory apertures of the early spiral are visible only in large and well-preserved specimens. The main aperture is bordered by large pustules. The well-defined sutures of the end stage are straight. Those of the initial stage are slightly curved. The walls are finely perforate and the surface is covered with strong and rather uniform pustules. The species coils to the right and to the left.

Size: The length of the test ranges from 0.35 mm to 0.6 mm. Dimensions of the holotype: length. 0.58 mm; diameter of end chamber, 0.4 mm; diameter of the two preceding chambers, 0.47 mm; diameter of main aperture, -+-0.11 mm: diameter of accessory aperture of end chamber, ±0.07 mm.

Extra details from original publication
The species is distinguished by its symmetrical, subquadrate test and in- distinct initial spiral, and by the main aperture being situated directly opposite the suture line.

This species occurs very abundantly in the upper Oligocene of Saipan. The same form is known as an undescribed index fossil for the Oligocene of Trinidad and eastern Venezuela. A specimen. showing better preservation of the wall surface than the Saipan specimens, is illustrated from the Cipero formation of Trinidad (pl. 1, fig. 5).

Editors' Notes
The name has often incorrectly been cited as Globigerinoides subquadratus Brönnimann 1954, but since the genus is feminine the correct form is Globigerinoides subquadrata and this was the name used in the original descrition.

References:

Spezzaferri, S., Olsson, R. K. & Hemleben, C. (2018c). Taxonomy, biostratigraphy, and phylogeny of Oligocene to Lower Miocene Globigerinoides and Trilobatus. In, Wade, B. S., Olsson, R. K., Pearson, P. N., Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 46(Chap 9): 269-306. gs V O

Todd, R., Cloud, P. E., Low, D. & Schmidt, R. G. (1954). Probable occurrence of Oligocene in Saipan. American Journal of Science. 252: 673-682. gs V O


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Globigerinoides subquadrata compiled by the pforams@mikrotax project team viewed: 14-5-2021

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