Pseudochablaisia subglobosa gen. et sp. nov., a new pfenderinid foraminifera from the Upper Cretaceous of Iran

Abstract

A new microgranular-imperforate foraminifera, attributed to the family Pfenderinidae, is described as Pseudochablaisia subglobosa gen. et sp. nov. from the upper Maastrichtian Tarbur Formation (Zagros Zone, SW Iran). It occurs in inner platform wackestones/packstones associated with other larger benthic foraminifera (e.g., Loftusia, Omphalocyclus, Gyroconulina) and dasycladacean green algae (e.g., Cymopolia, Dissocladella, Thyrsoporella). Pseudochablaisia gen. nov. is compared with possible ancestral morphotypes, the Middle Jurassic to Oxfordian homeomorph Chablaisia Septfontaine, 1978 and sections of a taxon classically assigned to the middle-Late Cretaceous “Nezzazatinella” Darmoian (1976) which type-material is incompletely known from loose isolated specimens. These two homeomorphic taxa and the new genus Pseudochablaisia possess a trochospirally coiled test, with a pseudokeriothecal wall texture (sometimes hardly visible). The central structure of the test comprises an umbilical (“siphonal”) hollow columella in early stages continuing in a deep umbilical cavity in later stages. The chamber interior is occupied by a zone of coalescence of the septa and a septal button, lacking in sections of “Nezzazatinella".