PEARSONITES, A NEW PALEOGENE PLANKTONIC FORAMINIFERAL GENUS FOR THE BROEDERMANNI LINEAGE

摘要

The new genus Pearsonites with P. broedermanni as type species is herein formalized to accommodate the early to middle Eocene globorotaliform taxa of the broedermanni lineage with a wall texture bearing muricae. Our analysis of specimens from the Pacific Ocean reveals a substantial similarity in wall structure with the genus Acarinina. In particular, the development and organization of the muricae, the hourglass shape of the pores, and the morphological features suggest that Pearsonites nov. gen. evolved from Acarinina in the late Paleocene. Herein we group three species previously considered morphologically and evolutionarily related to the Paleocene genus Igorina Davidzon, 1976, within Pearsonites nov. gen.: P. broedermanni (Cushman & Bermudez, 1949), P. lodoensis (Mallory, 1959), and P. anapetes (Blow, 1979). Species assigned to Pearsonites nov. gen. are relatively common in the stratigraphic interval from the late Paleocene (Zone P5) to the middle Eocene (Zone E9).