Architecture and revision of the pellatispirines, planispiral canaliferous foraminifera from the Late Eocene tethys

A review of discoidal to spherical pellatispirine taxa reveals the presence of three different cavity sytems in their architecture: chamber cavities connected by intercameral foramina, interlocular spaces transformed into the canal system, and interlamellar spaces. The latter may be inflated to lateral chamberlets, are fed by canal orifices and covered by primary, bilamellar, perforate walls, which may or may not support secondary lamellation added during subsequent growth of the shell. Whereas the inflated interlamellar cavities are interpreted as greenhouses for endosymbiontic algae, an interpretation of narrow and low interlamellar cavities in spherical to lenticular forms as brood chambers is not fully convincing.