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Linked specimens: USNM-219445
Current identification/main database link: Tenuitella parkerae (Brönnimann & Resig, 1971)
The very small test consists of about 12 to 13 chambers arranged in a flat trochospire with 5 chambers in the final whorl. The early subglobular chambers increase very slowly in size as added; those of the final whorl, however, increase rapidly, and at the same time they start to become more and more elongate in a radial direction. The final chamber is about 75 microns long and about 50 microns wide and makes up half of the maximum diameter of the test. This long chamber of bulbous appearance clearly dominates the test. Whereas the minute initial chambers, which are not radially elongate, on the spiral side are separated by oblique sutures, those of the final whorl are separated by radial, well-incised sutures, so that the chambers of the final whorl are well separated peripherally and produce a lobate outline of the test. The sutures on the umbilical side are radial and well incised. In lateral view, the chambers of the final whorl are distinctly compressed in an axial direction. In umbilical view, the chambers extend into the shallow and small umbilicus.
The aperture is an umbilical-extraumbilical arch with a distinct thin-walled plate-like lip with a faintly pustulate border.
The wall is calcareous, thin, almost transparent in stratigraphically young individuals, and, under the light microscope, of a brilliant appearance. As shown by the scanning micrographs (Plate 43,Figure 7) the surfaces of the first three chambers are finely pustulate in the vicinity of the umbilicus. The ultimate chamber also shows small pustules on the plate-like lip and on the apertural face above the lip. The surface of the umbilical side is very finely granular, and a few pinpoint-like wall pores can be detected toward the apertural face.
Size: The maximum diameter of the holotype is about 150 microns, and its maximum axial height is about 60 microns. The holotype, illustrated on Plate 43, Figure 7, is from Core CAP HG 41, 0-1 centimeter. The specimen coils to the left. The species is named for Frances L. Parker, Scripps Institution of Oceanography, La Jolla, who kindly donated the material.
Etymology: The species is named for Frances L. Parker, Scripps Institution of Oceanography, La Jolla, who kindly donated the material.
Extra details from original publication
Remarks: The early stage of Globorotalia (T.) parkerae, n. sp., recalls the coiling as seen in Globorotalia (Turborotalia) pumilio Parker, 1962, described from the Recent of CAP41HG, 0-1 centimeter. The adult stage of Globorotalia (T.) parkerae develops the characteristic elongate chambers and the lob ate outline of the test and is quite different from Globorotalia (T.) pumilio Parker, 1967 (Pl. 18, fig. 5 a-c). We have figured this species by a scanning micrograph of a topotype,Plate 48, Figure 1. The holotype of Globorotalia (T.) parkerae originates from the same sample as the holotype of Globorotalia (T.) pumilio. The maximum diameter of paratypes of Globorotalia (T.) parkerae from CAP HG41, 0-1 centimeter, ranges from about 100 to 160 microns. In the material from Hole 62-1, most of the individuals referred to as Globorotalia aff. Globorotalia (T.) parkerae exhibit similar morphologic features as the holotype and the paratypes of Globorotalia (T.) parkerae. As shown by the scanning micrographs, Plate 48, Figures 5, 6 and 7, the radial elongation of the final chamber is less than that shown by Globorotalia (T.) parkerae. In addition, the walls are less transparent and are perforated by rather large,round, irregularly distributed wall pores, which seem to be absent in Globorotalia (T.) parkerae. The aperture of Globorotalia aff. Globorotalia (T.) parkerae does not seem to have the plate-like lip. The surface of the walls is brilliant to dull and, besides the perforations, possesses also distinct rounded pustules which are particularly well developed on the ultimate and penultimate chambers. The early chambers of the final whorl show only a very few perforations and no pustules. It seems that perforations and pustules are morphologically interdependent. The morphologic differences between Globorotalia (T.) parkerae and Globorotalia aff. Globorotalia (T.) parkerae as exhibited by the scanning micrographs, may perhaps suggest that the latter should be taxonomically separated from Globorotalia (T.) parkerae. The maximum diameter of specimens of Globorotalia aff. Globorotalia (T.) parkerae from Hole 62.1, Core 3, Section 2, Bottom sample, ranges from about 70 to 150 microns, which agrees well with the maximum diameters measured of Globorotalia (T.) parkerae. The comparison of the scanning micrographs of Globorotalia aff. Globorotalia (T.) parkerae, with those of Globorotalia (Turborotalia) anfracta Parker, 1967, from Hole 62.1, Core 3, Section 2, Bottom samples, Plate 43, Figures 2, 3 and 6, shows a different test morphology but similar irregularly distributed large rounded pores. Similar perforations occur also on Globigerina microfoliata Brönnimann and Resig, n. sp., Plate 6, Figures 4, 5 and 6, and Plate 43, Figure 1, and on Globigerina aff. Globigerina quinqueloba Natland, 1938, Plate 43,Figures 8 and 9, both of which have been encountered in the same sample from which we described Globorotalia aff. Globorotalia (T.) parkerae and Globorotalia (T.) anfracta (pi. 43, fig. 2, 3, 6). We do not think that these affinities are accidental, but rather that they reflect a related genetic make-up which cannot be expressed by our actual and admittedly artificial taxonomic system. We refer to a similar suggestion regarding the grouping proposed for the representatives of the species Globigerinita glutinata (Egger), 1893. Globorotalia (T.) parkerae clearly differs in its outline,characterized by the strongly radially elongate final chamber, from Globorotalia (Turborotalia) neominutissima Bermúdez and Bolli, 1969, with its more rounded-lobate outline, described from the Pliocene Cumana Formation, Estado Sucre, Venezuela (Bermúdez and Bolli, 1969, pl. 13, fig. 10-12). According to the description, Globorotalia (T.)neominutissima is a small species, the maximum diameter of the holotype measures about 210 microns, and the wall is strongly pustulate. The aperture, to judge from the illustration, however, is more umbilical-extraumbilical than peripheral as in Globorotalia (T.) parkerae, Globorotalia aff.Globorotalia (T.) parkerae, and Globorotalia (T.) anfracta. This feature combined with the umbilically overhanging final chamber places Globorotalia (T.) neominutissima rather in the neighborhood of Globigerina quinqueloba Natland or perhaps Globigerina multiloba Romero, 1965.
Globorotalia (Turborotalia) parkerae compiled by the pforams@mikrotax project team viewed: 25-10-2020
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