Catalog - Globigerina praebulloides occlusa

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Globigerina praebulloides occlusa

Citation: Globigerina praebulloides occlusa Blow & Banner 1962

Type specimens: Plate IX U-W; Fig. 14 (i-ii)

Type sample (& lithostrat): sample FCRM 1922

Type locality: Lindi area. Tanzania

The fairly small test consists of about two to three whorls of subglobular to ovoid, fairly inflated chambers arranged in a low trochospire. The equatorial profile in ventral view is subquadrate to subtrapezoid and the equatorial periphery is strongly lobulate. The axial periphery is broadly rounded, the ventral sides of the chambers being more strongly convex than the dorsal sides. The chambers are regularly and fairly rapidly enlarging; in ventral view they are distinctly ovoid, whilst in dorsal view they are reniform, becoming hemi- spherical. The sutures are distinctly, broadly and deeply depressed. The dorsal intercameral sutures are initially curved but become radial during ontogeny. The spiral suture is lobulate and the spire projects above the plane of the dorsal surface. The umbilicus is open but narrow and shallow; as the apertural faces ofthechambersareslightlyflattened, the umbilicus is fairly sharply delimited, although it does not possess a clear quadrangular outline. The intraumbilical aperture of the last chamber is a very low, asymmetrical arch, more steeply arched at its anterior end; it lacks a lip or rim. Typically, relict apertures of the earlier chambers cannot be seen within the umbilicus. The wall is fairly thick, uniformly perforate and distinctly hispid; advanced forms become distinctly punctate. The hispidity is strongest over the peripheral parts of the chambers, on the dorsal surface and within the umbilicus.

Maximum diameter of holotype: 0·37 mm

Globigerina trilocularis d'Orbigny, Romer, 1838 (? not d'Orbigny, 1826, nom. nud.; not Globigerina trilocularis Deshayes, I832), Neues Jb. Min. Geol. Paliiont, p. 390, pl. 3, fig. 41 a.
G. cf. trilocularis d'Orbigny, Bolli, 1957 (part) (not G. trilocularis Deshayes, 1832), Bull. U.S. Nat. Mus. 215, llO, 163, pl. 22, figs. 9a-c (not figs. 8a-c); pl. 36, figs. 3a-b.
G. globularis Roemer; Drooger & Batjes, 1959 (not Roemer, 1838), Proc. K. Akad. Wet. Amst., ser. B, 62, no. 3, p. 174, pl. 1, fig. 2.

Remarks: Globigerina praebulloides occlusa differs from G. praebulloides praebulloides in possessing a smaller, shallower umbilicus, a smaller, lower aperture which lacks a lip or rim and in possessing a slightly thicker, rougher and more coarsely perforate wall. G. praebulloides occlusa is distinguished from G. praebulloides leroyi in possessing a shallower umbilicus and an asymmetrical aperture which lacks a lip. The chambers of G. praebulloides occlusa are more embracing than those of G. praebulloides praebulloides, but are less tightly embracing than those of G. praebulloides leroyi.

It is probable that the form illustrated by Roemer (1838) as 'G. trilocularis d'Orbigny' from marine sands of North Germany, near Osnabruck (probably Oligocene), is synonymous with G. praebulloides occlusa subsp. nov. However, Roemer's specimen seems distinct from that drawn by d'Orbigny (published by Fornasini, 1897), and in any case G. trilocularis d'Orbigny, 1826, was nomen nudum. With the assistance of MM. Marie and Lys, we searched the d'Orbigny collections in Paris, but were forced to conclude that all d'Orbigny's specimens which he referred to G. trilocularis have been lost. As the name was first validly described by Deshayes in 1832, the taxon should be credited to him and not to d'Orbigny, and only Deshayes' specimens can now be considered to rank as availble syntypes. Unfortunately, Deshayes did not Illustrate his form and we have not been able to locate his collections. Consequently it is not possible to use the name G. trilocularis Deshayes until his material is redescribed. The published illustrations of Fornasini (1898) and Roemer (1838) are, together with d'Orbigny's 'planches inedites', published by Fornasini, without status.

Stratigraphical range: This subspecies is known to occur in the Middle Eocene and ranges throughout the Upper Eocene and Oligocene to about the middle part of the Aquitanian (Globorotalia kugleri Zone) (see also §VII, p. 136). It has been observed in the Oligocene of Offenbach and Elmsheim, the Stampian of south-wet France (Cambes, Gironde) as well as in the Aquitanian of Moulin de l'Eglise and Escornebeou, Aquitaine. It is widely distributed in both the Caribbean and East African regions.

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

Spezzaferri, S., Olsson, R. K., Hemleben, C., Wade, B. S. & Coxall, H. K. (2018d). Taxonomy, biostratigraphy, and phylogeny of Oligocene and Lower Miocene Globoturborotalita. In, Wade, B. S., Olsson, R. K., Pearson, P. N., Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 46(Chap 8): 231-268. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina praebulloides occlusa Blow & Banner 1962

Globigerina praebulloides occlusa

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