Catalog - Globigerina turritilina turritilina

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.

Globigerina turritilina turritilina

Citation: Globigerina turritilina turritilina Blow & Banner 1962

Type sample (& lithostrat): sample FCRM 1964

Type locality: Lindi area, Tanzania

The large or fairly large test consists of about three whorls of rapidly enlarging, inflated, weakly em- bracing chambers, arranged in a high trochospire with four chambers in each whorl. The equatorial profile of the test is subquadrate and the equatorial periphery is strongly lobulate. In axial profile the test is ovoid, the dorsal surface being strongly con- vex (high-spired) and the ventral surface being inflated but relatively weakly convex. The axial profile of the test is strongly lobulate, and the axial profile of each chamber is broadly and smoothly curved, no dorsa-peripheral shoulder being appa- rent. The sutures are broadly and deeply depressed. The spiral suture is strongly lobulate. The dorsal intercameral sutures are weakly curved to sub- radial throughout, owing to the height of the spire and the strong inflation of the chambers. The ventral intercameral sutures are subradial. In dorsal view, the chambers are semicircular to reni- form and in ventral and axial views they are sub- ovoid. The umbilicus is moderately broad, deep, open and of quadrate outline. It is not sharply delimited, as the apertural faces of the chambers are only weakly flattened. The aperture of the last chamber is a fairly low arch, practically sym- metrical in shape, and it is entirely restricted to a position within the umbilicus which it directly faces. The relict aperture of the penultimate chamber may be visible within the umbilicus. The final aperture is bordered by a distinct lip throtighou tits length, often broadest at its mid-point. The wall is fairly thick, uniformly and fairly coarsely perforate. The surface is weakly cancellate and finely hispid. The hispidity is strongest on the ventral sides of the chambers and their umbilical margins.

Maximum diameter of holotype 0·60 mm

The only known members of the Globigerinidae which grossly resemble Globigerina turritilina turritilina are G. turritilina praeturritilina subsp. nov. (see p. 99), G. helicina d'Orbigny, 1826 (see Banner & Blow, 1960a), and Globigerinoides mitrus Todd (1957; from the Tagpochau limestone, Burdigalian of Saipan), which differs generically and is probably quite unrelated. Globigerina helicina d'Orbigny has less globular chambers, a less lobulate periphery, a lower dorsal spire and a less hispid test than G. turritilina turritilina. The larger specimens of Globigerina turritilina turritilina from both the uppermost Eocene and Oligocene populations frequently possess aborted final chambers which are reduced in size and are of variable shape and position within the limits of the ventral side. The holotype may be seen (Plate XIII E-G) to have lost such an aborted final chamber, although the paratype (Plate XIIID) still possesses one. (See also p. 146.)

Stratigraphical range: Globigerina turritilina turritilina has been found to occur, in East Africa, only in the uppermost Bartonian and in the Lattorfian-Rupelian (cf. G. turritilina praeturritilina). Dr C. G. Adams has kindly shown us a sample containing this form from the mouth of the Benaleh River, Baram Headwaters, Sarawak, where it is associated with the Oligocene Nummulites fichteli (see also p. 71). This species has not been recorded or observed by us in the Globigerina ampliapertura Zone, Cipero formation, southern Trinidad, or in equivalent horizons in the Caribbean-Central Amencan regions, including the Vicksburgian of the American Gulf States. Similarly, it has not been recorded from, or observed in, the Upper Eocene of these areas, so that, as the form appears to be a tropical or subtropical species, this is confirmatory evidence for the absence of both the uppermost Eocene and Oligocene in the Central American Region.

References:

Blow, W. H. & Banner, F. T. (1962). The mid-Tertiary (Upper Eocene to Aquitanian) Globigerinaceae. In, Eames, F. E., Banner, F. T., Blow, W. H. & Clarke, W. J. (eds) Fundamentals of mid-Tertiary Stratigraphical Correlation. Cambridge University Press, Cambridge 61-151. gs

Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (2006a). Taxonomy, biostratigraphy, and phylogeny of Eocene Globigerina, Globoturborotalita, Subbotina, and Turborotalita. In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 41(Chap 6): 111-168. gs O

Pearson, P. N. & Wade, B. S. (2015). Systematic taxonomy of exceptionally well-preserved planktonic foraminifera from the Eocene/Oligocene boundary of Tanzania. Cushman Foundation for Foraminiferal Research, Special Publication. 45: 1-85. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina turritilina turritilina Blow & Banner 1962

Globigerina turritilina turritilina

References:

Add Comment

Comments