Catalog - Pulleniatina spectabilis praespectabilis

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Pulleniatina spectabilis praespectabilis

Citation: Pulleniatina spectabilis subsp. praespectabilis Brönnimann & Resig 1971

Type locality: SW Pacific, Eauripik Ridge, Hole 62.1, Core 12, Sec.4, 15-17cm, Zone N.20

Type repository: Washington; USNM

The large-sized test is a spirally slightly, umbilically strongly convex trochospire having six chambers in the final whorl. The total number of chambers is greater than 11. The exact number is difficult to determine because of the masking of the early trochospire by shell material. The outline, as seen from the spiral and from the umbilical side is slightly lobate in the early portion of the final whorl. This lobation disappears in the final two chambers. We refer to Banner and Blow's illustration of an apertural view (1967, pi. 2, fig. lb) which shows that the ultimate chamber does not extend umbilically completely over the penultimate one. The dorsal cameral sutures are somewhat oblique in the early portion of the test and virtually radial between the last three chambers. In lateral view, the test shows the slightly convex dorsal surfaces of the chambers of the final whorl, the rounded convex early portion of the test, and the strong ventral convexity formed by the ventrally extended and axially over-lapping chambers. There is no carina nor pseudocarina in the sense of Parker (1967), but a rounded to subrounded peripheral shoulder. The umbilical view exposes the strong axial overlapping of the penultimate chamber which closes any umbilical depression that might have existed before the addition of the penultimate chamber. The ultimate chamber does not extend over the axial portion of the test, hence it is ventrally much shorter than the penultimate chamber. The aperture is a large interiomarginal opening extending from the umbilicus almost to the periphery of the test.
Its length is about 275 microns, and its height about 50 microns. The calcareous wall is thick, about 50 to 75 microns at the aperture, and the surface is smooth excepting near the aperture where the surface of the fourth and fifth chamber of the final whorl is distinctly pustulate umbilically. The holotype of Pulleniatina spectabilis praespectabilis coils to the left.

The maximum diameter of the holotype is 625 microns. Its axial height is about 500 microns. It is from Hole 62.1,Core 12, Section 4, Zone N. 20 (including N. 19). The specimen is illustrated on Plate 19, Figures 44 and 7.

Pulleniatina spectabilis praespectabilis differs from Pulleniatina spectabilis spectabilis Parker, 1967, by the well-rounded, not pinched-rounded, shoulders of the chambers of the last whorl as illustrated on Plate 19, Figures 4 and 7 (pseudocarina of Parker, 1967, p. 179) and by the convex-rounded initial portion of the trochospire as seen in lateral view. The ultimate chamber of Pulleniatina spectabilis spectabilis extends ventrally farther over the penultimate chamber (Parker, 1965, text-fig. 1 a-c; Banner and Blow, 1967, pi. 2, fig. 2 a-c). In other morphologic aspects the two subspecies are similar. We are here restricting the usage of Pulleniatina spectabilis spectabilis to those forms as illustrated by Parker (1965, text-fig. 1 a-c, 2; 1967, pi. 28, fig. 2 a-c) and by Banner and Blow (1967, pl. 2, fig. 2 a-c) which show the distinctly pinched periphery. Pulleniatina spectabilis spectabilis has a very short range in Hole 62.1, from Sections 4 to 6 of Core 11 only. It seems to represent the final evolutionary development of Pulleniatina spectabilis praespectabilis which occurs shortly after the evolutionary inception of Sphaeroidinella dehiscens immatura (Cushman), 1919. This agrees well with Parker's remark (1965, p. 151) that the range of Pulleniatina spectabilis spectabilis can be placed quite precisely, at the same time, or shortly after the appearance of Sphaeroidinella dehiscens. In Hole 62.1 it occurs shortly after the first appearance of Sphaeroidinella dehiscens immatura, in Section 6 of Core 12. Pulleniatina spectabilis praespectabilis appears before Pulleniatina spectabilis spectabilis and, in the writers' opinion, is ancestral to Pulleniatina spectabilis spectabilis which has been recorded in Hole 62.1 only in Core 11, Sections 4 to 6, Zone N. 20 (including N. 19), where it
is associated with the subspecies spectabilis prae spectabilis. According to Banner and Blow (1967) and to Parker (1967), Pulleniatina spectabilis spectabilis evolved from Pulleniatina primalis Banner and Blow, 1967. This seems to be quite possible in view of the earlier beginning of the morphologically affine Pulleniatina primalis in the lower to middle part of Zone N. 17, Hole 62.1, Section 2 of Core 20. Parker's remark (1967, p. 174) that untypical specimens of Pulleniatina spectabilis occur in LSDH 78 P for about 200 centimeters above the base of Zone N. 19 (here included in Zone N. 20) concerns most probably Pulleniatina spectabilis praespectabilis.

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: Pulleniatina spectabilis subsp. praespectabilis Brönnimann & Resig 1971

Pulleniatina spectabilis praespectabilis

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