Catalog - Planoglobulina brazoensis

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Other pages this level: P. brazoensis, P. meyerhoffi, P. taylorana, P. transcaucasica

Planoglobulina brazoensis

Citation: Planoglobulina brazoensis Martin 1972

Type age (chronostrat): Maastrichtian

Type locality: from 18 feet above the base of an exposure on the south bank of Walter Creek, 6 mi. N15E of Cameron, Milam County, TX

Type repository: Washington; USNM

Test flabelliform, inflated, especially in early portion. Six rapidly expanding chambers in biserial portion; 10 inflated, globular chambers in multiserial portion. Sutures fairly distinct, depressed. Coarse, discontinuous, longitudinal costae over entire test, separated by 2 or more rows of randomly arranged pores; costae somewhat finer on last row of chambers. Arched, basal apertures on front and back of all but outermost chambers in the last row; outermost chambers with apertures on front only, facing inward.

Holotype measures 525µm in length, 475µm in width, and 275µm in maximum thickness. Other specimens vary from 500 to 550µm, in length; 450 to 525µm in width; and 250 to 300µm maximum thickness.

Pseudotextularia elegans Rzehak var. acervulinoides (Egger), GLAESSNER 1945, pl. 10, figs. 15c, d.
Pseudotextularia (Racemigumbelina) fructicosa (Egger), BERGGREN 1962, p. 22, pl. VI, figs. 6a, b.
Pseudotextularia acervulinoides (Egger), WILLE-JANOSCHEK 1966
Planoglobulina acervulinoides (Egger), PESSAGNO 1967, p. 271,pl. 87, fig. 14. 1966, p. 119, pl. 8, fig. 8

Remarks: P. brazoensis, n. sp., differs from P. acervulinoides (Egger), in its less symmetrical, more inflated test, narrower costae, and fewer number of chambers (15 to 18).

Range: G. contusa-stuartiformis Assemblage Zone, uppermost G. gansseri Subzone to A. mayaroensis Subzone.

Occurrence: In Texas P. brazoensis, n. sp., occurs in the late Maestrichtian (uppermost G . gamseri Subzone) Kemp Clay of Falls and Milam counties (TX 267 of Pessagno; TX 9AH of Smith, see appendix).
In Mexico P. brazoensis, n. sp., is abundant in the late Maestrichtian portion of the Papagallos Shale (MX 174 of Pessagno, see appendix).
The specimen figured by Berggren (1962, pl. VI, fig.6) from the late Maestrichtian of southern Scandinavia is Planoglobulina brazoensis Martin, n. sp., not Pseudotextularia (Racemiguembelina) fructicosa (Egger), R. fructicosa is conical in shape and has coverplates, with accessory apertures, which extend over the last few series of circumferentially arranged chambers (see plate 4, fig. 3c).

References:

Martin, S. E. (1972). Reexamination of the Upper Cretaceous planktonic foraminifera genera Planoglobulina and Ventilabrella Cushman. Journal of Foraminiferal Research. 2(2): 73-92. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Planoglobulina brazoensis Martin 1972

Planoglobulina brazoensis

References:

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