CATALOG OF ORIGINAL DESCRIPTIONS: Globigerinoides quadrilobatus praeimmaturus Brönnimann & Resig 1971

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 quadrilobatus praeimmaturus
Other pages this level: << < G. macrostoma, G. minuta, G. mitra, G. muratai, G. nuttalli, G. obliqua, G. obliquus amplus, G. obliquus extremus, G. parawoodi, G. parkerae, G. parva, G. pseudodubia, G. pseudoruber, G. pseudosellii, G. quadrilobatus hystricosus, G. quadrilobatus praeimmaturus, G. quadrilobatus primordius, G. ruber albus, G. ruber parkeri, 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> >>

Globigerinoides quadrilobatus praeimmaturus

Citation: Globigerinoides quadrilobatus praeimmaturus Brönnimann & Resig 1971
Rank: sub-species
Type locality: Ontong Java Plateau, Hole 64.1, Core 2, Sec 6, 15-17cm, Zone N.7/N.8
Type age (chronostrat): Miocene
Type specimens: PAL 219454
Type repository: Washington; USNM

Linked specimens: USNM-219454

Current identification/main database link: Trilobatus praeimmaturus (Brönnimann and Resig, 1971)


Original Description
he medium-sized subglobular to ovoid test is a low trochospire with 4 subglobular chambers, rapidly increasing in size, in the final whorl. The ultimate chamber virtually equals in size the previously formed portion of the test. The initial chambers are tightly coiled and their sutures masked by secondary shell substance. The outline of the test in umbilical and spiral view is broadly oval, almost equidimensional and oval, longer than wide, in side view. The general shape of the test compares well with that of Globigerinoides cellatus (Subbotina), 1958, as illustrated by Banner and Blow (1965, p. 108, text-fig. 5a,b). There is only a very slight umbilical depression. The "primary aperture" is a narrow, umbilical, interiomarginal slit of about 100 microns in length and less than 10 microns in height. The "primary aperture" follows the gentle umbilical rounding of the antepenultimate chamber,which is the middle chamber as seen in the umbilical view, and it is of the same height throughout. The "primary aperture" is devoid of any lip or rim and shows in the scanning micrograph (Plate 9, Figure 4) strong, blunt, composite pustules which are basically fused. Such strong pustules and interconnecting walls are typical for the entire surface of the test (Plate 9, Figure 1). They surround funnel-like depressions with small rounded pores in their centers of up to 5 microns diameter. On the earlier chambers of the final whorl,the pustules become completely fused laterally, developing around the wall pores a coarse polygonal meshwork. In a longitudinal section of a paratype from Hole 64.1, Core 2, Section 6, 15-17 centimeters, as illustrated by the scanning micrograph, Plate 9, Figure 2, the real primary aperture is not visible from the outside of the test. It is, in fact, hidden under the overhanging subglobular ultimate chamber and is represented by a large arched opening of about 45 microns height leading into the narrow space between ultimate and antepenultimate chambers. This narrow space opens then in the form of an incurved slit between ultimate and antepenultimate chambers,described above as "primary aperture".
On the spiral side a single, very small secondary opening, of about 20-micron diameter, also a gently incurved
elongate triangular slit, occurs between the last chambers of the ultimate and penultimate whorls. In contrast to the slit-like "primary aperture" this elongate secondary slit seems to be the real opening. The intercameral sutures of the final whorl are well incised. The calcareous wall is thick, with strong composite bluntly pointed pustules which surround the deeply set perforations in groups of 4 to 6.

Size: The holotype coils to the right. The maximum diameter of the holotype is about 220 microns; its axial height is about 188 microns. The holotype is from Hole 64.1, Core 1, Section 4, 33-35 centimeters; Zone N. 7/N. 8 and is illustrated on Plate 9, Figure 1.

Extra details from original publication
Globigerinoides quadrilobatus praeimmaturus Brönnimann and Resig, n. subsp., is related in its chamber arrangement to Globigerinoides quadrilobatus immaturus LeRoy, 1939, which occurs according to Blow (1969) from Zone N. 4 to Zone N. 23, and in its contours and slit-like "primary aperture"" to Globigerinoides cellatus (Subbotina), 1958. It differs from both species by its hidden primary aperture, and from Globigerinoides quadrilobatus immaturus also by the narrow slit-like ""primary"" opening and by its virtually equidimensional test as seen in umbilical and spiral view. From the similar subglobular trochospires of Globigerinoides sicanus praesicanus Brönnimann and Resig, n. subsp., and Globigerinoides pseudoselli Brönnimann and Resig, n. sp., it differs by the apertural features and by the position of the primary
aperture at the intersection of the sutures between the ultimate and penultimate-antepenultimate chambers and the penultimate and antepenultimate chambers in praesicanus and in pseudosellii (Plate 10, Figures 5, 6
and 8; Plate 9, Figures 7, 8 and 9). The longitudinally sectioned specimen illustrated by Plate 9, Figure 2, is
about 300 microns in maximum diameter. The maximum diameter of the ultimate chamber is about 250 microns and
its maximum height about 134 microns. These dimensions agree practically with the dimensions of the previously
formed test. The maximum thickness of the wall of the ultimate chamber of the preceding whorl is about 3 microns.
On the basis of the axial height, the linear increase from penultimate to ultimate whorl is 1:2. The maximum
diameters of paratypes from Hole 64.1, Core 1, Sections 1, 2 and 4, range from about 200 to 300 microns."

References:

Brönnimann, P. & Resig, J. (1971). A Neogene globigerinacean biochronologic time-scale of the southwestern Pacific. Initial Reports of the Deep Sea Drilling Project. 7(2): 1235-1469. gs V O

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


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Globigerinoides quadrilobatus praeimmaturus compiled by the pforams@mikrotax project team viewed: 21-4-2021

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