Sengoerina argandi, n. gen., n. sp., and its position in the evolution of Late Permian biseriamminid foraminifers

The name Sengoerina is proposed for a new biseriamminid genus characterized by a coiled stage of initially globular to progressively angular, biserial chambers followed by an uncoiled stage of angular, biserial chambers. Unli ke Dagmarita, it has a distinct coiled stage and lacks spine-like projectio ns at the outer margins of the chambers. Sengoerina constitutes the root st ock of the angular-chambered, dagmaritin-type biseriamminids which evolved from the globivalvulines in the Late Permian.