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On the systematics of rugoglobigerinids (planktonic Foraminifera, Late Cretaceous)

Georgescu M. D.

Studia Geologica Polonica

2005

Vol. 124

87-98

A subdivision of the Late Cretaceous planktonic foraminiferal family Rugoglobigerinidae is now proposed according to the nature and patterns in ornamentation as well as the development of peripheral structures. Typical rugoglobigerinids, namely those presenting meridionally arranged pustules, rugosities and costellae are retained within the subfamily Rugoglobigerininae. The sub- family Archaeoglobigerininae is now erected to accommodate taxa presenting chamber ornamen- tation consisting of not fused pustules, papillae, rugosities, and spines which are not arranged following a meridional pattern. In what concerns the peripheral structures, whose development is regarded as indicative for adaptation to deeper water environments. It is demonstrated that the two subfamilies, Rugoglobigerininae and Archaeoglobigerininae respectively, present quasi-parallel evolutionary strategies. The status of the genus Rugotruncana is revised. Transitional specimens between Archaeoglobigerina blowi and Rugotruncana subcircumnodifer from the Upper Campanian of the New Jersey coastal plain demonstrate that Rugotruncana is the only known double-keeled rugoglobigerinid, and is included in the subfamily Archaeoglobigerininae, rather than among the Globotruncanidae.