Some West African Cenozoic Agglutinated Foraminifers with Inner Structures: Taxonomy, Age and Evolution

Abstract

Compressed agglutinated foraminifers with characteristic inner structures are included in the family Tawitawiidae. They have a fanlike arrangement of incomplete inner partitions and triserial, biserial, uniserial, or combined series of chambers. The genera have an evolutive history that is in agreement with their biostratigraphic distribution. Pavopsammia, n. gen., with a triserial-biserial trending to uniserial arrangement of chambers is described in this family. Spiropsammiinae, n. subfam. is erected to include agglutinated foraminifers with fan-arranged, bulboid alveoles in planispiral or planispiral-uniserial chambers. Spiropsammia, n. gen. is described with two species: S. uhligi (Schubert) which has planispiral-uniserial chambers, and S. primula, n. sp. with only uniserial chambers. Two other species of agglutinated planispiral foraminifers with inner structures are also abundant in the Tertiary of West Africa: Reticulophragmium cf. venezuelanum and Hemicyclammina plana?. Some West African Cenozoic agglutinated foraminifers with inner structures: taxonomy, age and evolution