Catalog - Globoquadrina altispira conica

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Globoquadrina altispira conica

Citation: Globoquadrina altispira conica Brönnimann & Resig 1971

Type locality: SW Pacific, Eauripik Ridge, Hole 62.1, Core 30, Sec.1, 15-17cm, Zone N.15

Type repository: Washington; USNM

The large sized test is a high conical trochospire of four whorls with 4.5 chambers in the final whorl.
The initial portion of the trochospire is composed of very small chambers, and is rounded. Its sutures are not discernible because they are masked by shell substance.
The chambers of the following three whorls increase rapidly in size from whorl to whorl, but only gradually within the same whorl. The sutures are distinct and strongly depressed. This depression of the sutures and the subglobular, in radial direction somewhat flattened,chambers produce a lobate outline in umbilical, spiral and side views. The umbilicus is deep, open and exposes the apertures of the penultimate and ante penultimate chambers. The umbilical sides of the chambers are flattened and extend into pustulate, triangular tooth like extensions like those found in Globoquadrina altispira altispira (Cushman and Jarvis),1936. The large umbilical aperture shows a thin,smooth border on both sides of the triangular extensions, which may be heavily pustulate as shown by the scanning micrograph (Plate 22, Figure 1). The heavy calcareous wall is perforate, with pore openings of up to 10 microns in diameter. The surface is pustulate.Individual, elongate, distally blunt to pointed pustules occur above the more finely pustulate portion of the
flattened apertural face. These pustules fuse along their bases, and in the course of growth from four to six sided angular compartments each with a deeply set wall pore in its center. This polygonal meshwork is well developed on the first and second chambers of the final whorl.

he maximum diameter of the final whorl of the holotype is about 400 microns, its maximum axial height about 435 microns. The specimen coils to the left. It is illustrated on Plate 22, Figure 1, and comes from Hole 62.1, Core 30, Section 1,15 17 centimeters,Zone N.15.

Globoquadrina altispira conica, n. subsp., is not a common form, although it may occasionally occur in floods as in Hole 62.1 Core 30, Section 1, 15 17 centimeters, Zone N. 15. It differs from the spirally more rounded, globose Globoquadrina altispira altispira (Cushman and Jarvis), 1936, by the higher almost conical spiral side. In many individuals of Globoquadrina altispira conica the whorls are arranged in angular tiers as seen in lateral view. The height of the trochospiral itself is rather variable within a population. Comparison with Globoquadrina altispira altispira from Hole 62.1, Core 9, Section 3, Plate 38, Figure 1,exhibits for that form a more open umbilicus, almost smooth walled "teeth"" and a finer cancellated surface than in the new subspecies."

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 O

CATALOG OF ORIGINAL DESCRIPTIONS: Globoquadrina altispira conica Brönnimann & Resig 1971

Globoquadrina altispira conica

References:

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