Suborder Lagenina and other smaller foraminifers from uppermost Pennsylvanian-lower Permian rocks of Kansas and Oklahoma

摘要

The Late Pennsylvanian-Early Permian succession in southern Kansas and northern Oklahoma preserves a fairly complete and precisely dated record of dominantly marine sedimentation. Calcareous smaller foraminifers from these rocks are abundant and diverse, but they have not been documented in their entirety before now. Analysis of the local and global stratigraphic distributions of lagenoid taxa shows that the Nodosinelloides-Geinitzina evolutionary transition may be an internationally correlatable interval within the upper Gzhelian Stage. The local succession contains the oldest known occurrence of Geinitzina postcarbonica in the upper Hughes Creek Shale, slightly below the base of the Asselian Stage. Globally, the appearance of G. postcarbonica and other primitive congeners reliably indicates Asselian age. More advanced G. bisulcata n. sp. and G. indepressa appear locally in the Sakmarian and Artinskian stages, respectively. Species in Nodosinelloides, Protonodosaria, Vervilleina, and Syzrania appear locally in the upper Gzhelian Stage, but they are known from older strata elsewhere. Paleozoic lagenoids have been classified within the suborders Fusulinina and Lagenina. They are assigned here to the Lagenina on the basis of wall structure, which differs only slightly from that in Recent nodosariaceans, and on evidence of evolutionary continuity with unquestioned Mesozoic Lagenina. The Lagenina are considered a monophyletic group that originated with the family Syzraniidae in Moscovian time. Two species, Syzrania bulbosa and Geinitzina bisulcata, are described as new.