Catalog - Globorotalia (Turborotalia) planispira

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Globorotalia (Turborotalia) planispira

Citation: Globorotalia (Turborotalia) planispira Brönnimann & Resig 1971

Type locality: S W Pacific, Eauripik Ridge, Hole 62.1 1 Core 6, Sec.5, 15-17cm, Zone N.21

Type repository: Washington; USNM

The small test of about 12 to 13 chambers forms a dorsally flat trochospire with 5 chambers in the final whorl. The outline of the test both in dorsal and ventral view is subcircular. The chambers increase gradually in size as added with the exception of the ultimate chamber which is smaller than the penultimate one and slightly displaced toward the umbilical side. The chambers are tangentially longer than radially, at least the 3 to 4 final ones. The penultimate chamber is about 100 microns in tangential and about 75 microns in radial direction, measured in spiral view.
They are distincly compressed in axial direction and spirally more flattened than umbilically. Peripherally they are broadly rounded. The well-incised cameral sutures are oblique on the spiral side throughout most of the ontogeny and radial on the ventral side. The initial coil is very slightly depressed in respect to the chambers of the final whorl. The umbilical side shows the chambers of the final whorl enclosing a deep and small axial cavity of about 20 microns diameter. The aperture is a low slit extending from the umbilicus to the periphery beneath a thick-walled, pustulate platelike lip of about 10 microns maximum width. The calcareous wall is perforate and its surface pustulate. Over the early umbilical portion of the test the pustules become rather prominent and pointed. The scanning micrograph, Plate 44, Figure 4, shows that the larger, rounded, blunt pustules, forming funnel-like polygonal compartments around the depressed widely spaced small wall pores, are composed of numerous smaller units. The specimen coils to the right.

The maximum diameter of the holotype is about 240 microns, its axial height about 125 microns. It is illustrated on Plate 44, Figure 4. It is from Hole 62.1,Core 6, Section 5, 15-17 centimeters, lower part of Zone N. 21.

The characteristic features of Globorotalia (T.) planispira, n. sp., are the consistently flat trochospire, the tangentially wide chambers of the final whorl, the slight umbilical displacement of the final chamber, which is usually smaller than the penultimate one, the prominent apertural plate-like rim, and the composite pustules and interconnecting polygonal walls. All examined paratypes coil to the right. The new species is associated almost throughout its range with Globorotalia (T.) pseudopumilio Brönnimann and Resig, n. sp.
In a paratype illustrated on Plate 44, Figure 2, a supplementary spiral aperture occurs at the intersection of the suture between the ultimate and penultimate chambers with the spiral suture. Besides the supplementary dorsal aperture of about 20 microns maximum width, it exhibits an irregular subglobular chamber covering part of the initial, flattened coil. The supplementary aperture is surrounded by an almost smooth, slightly rounded, imperforate border. The apertural surface above the lip is also imperforate and covered with small individual pustules. Rounded wall pores start to occur immediately above the point where they are surrounded by fused large, bluntly rounded,composite pustules. A linear surface pattern created by aligned small pustules occurs radiating toward the secondary aperture. This radiating pattern is also discernible on the ultimate chamber of the specimen illustrated by the scanning micrograph of a side view,
Plate 44, Figure 5. Also, the paratype illustrated by the scanning micrograph, Plate 44, Figure 1, exhibits, on the umbilical side, the radiating linear surface pattern.The maximum diameter of paratypes, including the questionable form, ranges from about 130 to 250 microns. Globorotalia (T.) planispira is similar to Globorotalia (T.) pseudopumilio Brönniman and Resig,n. sp., in the multiple pustules, the flattened and occasionally somewhat depressed initial coil, the aspect of the perforations, but differs from Globorotalia (T.)pseudopumilio mainly in the dorsally flattened chambers of the final whorl, in the umbilically displaced final chamber, in the subcircular outline as seen in dorsal view and in the absence of "canaliculate"" pustules."

References:

Brönnimann, P. & Resig, J. (1971). 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. Initial Reports of the Deep Sea Drilling Project. 7(2): 1235-1469. gs O

CATALOG OF ORIGINAL DESCRIPTIONS: Globorotalia (Turborotalia) planispira Brönnimann & Resig 1971

Globorotalia (Turborotalia) planispira

References:

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