Diagnosis - A Globotruncana contusa (Cushman) [Pulvinulina arca Cushman var. contusa. 1926 ] with much lower spire, less plicated surface and less elongated chambers on dorsal side.

Description - Test large, robust, spiroconvex, coiled in a relatively high trochospire; dorsal side moderately convex, gently plicate and undulate; ventral side almost flat and weakly inflated; equatorial periphery bluntly polygonal, with two well developed, heavily beaded, marginal keels which enclose a narrow, slightly inclined peripheral band and tend to weaken towards the last chamber where the ventral keel is completely reduced; axial periphery subangular, subtruncate; chambers on the dorsal side 17, arranged in 3 dextrally coiled whorls; initial chambers very small, globular, weakly inflated, increasing very slowly in size, followed by much larger, subglobular, inflated chambers which tend to be roughly crescentic towards the last whorl and which increase moderately in size; the last whorl composed of 5 large, narrow, distinctly elongated chambers, roughly crescentic in the early part, irregular, folded and undulate in the last two chambers, which increase moderately in size although the last chamber is slightly smaller than the penultimate; the 5 chambers on the ventral side are large, angular, roughly rectangular, strongly elongated and increase moderately in size except for the last one; sutures on the dorsal side short, curved, beaded in the early part and distinctly elongated, curved, undulated, raised, thickened and beaded later; on the ventral side the sutures are slightly curved in the early part, straight, radial and depressed in the later; umbilicus roughly stellate in outline, relatively wide, deep, bordered by thick beaded ridges which fade out gradually towards the last chamber; it is covered by complex tegilla of which remnants are still preserved; primary apertures interiomarginal, umbilical; tegilla, with accessory apertures, only poorly preserved; wall calcareous, perforate except for the imperforate keels, peripheral band and tegilla; surface delicately papillose, especially in the early part and on the ventral side.

Remarks. - This form represents the maximum development of a whole series of transitional stages between G. fornicata fornicata Plummer and G. contusa contusa (Cushman). It could neither be included in the former species, although it occurs with it, nor in the latter as it is morphologically slightly different and stratigraphically older. It is more closely related to G. contusa contusa (Cushman) of which it is therefore considered a subspecies.
Pozaryski and Witwicka ( 1956, Poland, Serv. Geol. Pologne, Bull., vol. 102, pp. 5-30) mentioned the occurrence of what they described as G. fornicata var. contusa in the Upper Campanian of the Lublin Basin, central Poland, but gave no figure or description. Their form may belong to the present subspecies or it may be transitional to G. fornicata fornicata Plummer. However, as all forms of G. fornicata which show transitional characters to G. contusa are included in the present subspecies, Pozaryski and Witwicka's form is considered to belong here."

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