A new Idalina (Milioloidea, benthic Foraminifera) and some associated fauna from the upper Maastrichtian Tarbur Formation of SW Iran

Abstract

ABSTRACT The upper Maastrichtian Tarbur Formation of the Zagros Zone, SW Iran, contains a rich assemblage of larger benthic Foraminifera including agglutinating, porcelaneous, and lamellar-perforate taxa. The occurrence of such a diversified foraminiferal fauna represents a prominent high diversity that took place in the Arabian platform during the latest Cretaceous. Several new species have been reported in the past decades from these carbonates, whereas many others have been described in recent times. However, the list of unknown taxa is still far from being complete. In the present contribution, we describe a new taxon referred to the miliolid genus Idalina. Idalina praecaenozoica n. sp. displays the typical basal layer that characterises the genus, whereas it differs from the other well-known Cretaceous and Paleogene allies by some morphometrical parameters. Compared to the dispersal of other Maastrichtian larger Foraminifera, the paleogeographic distribution of Cretaceous Idalina appears less extensive. Pseudonummoloculina kalantarii, another characteristic miliolid from the Tarbur Fm. is here figured with poorly known axial sections. The latest representative of the Siderolitidae, the late Maastrichtian marker taxon Canalispina iapygia is here reported as well. All such taxa give further evidence to the enhanced biogeographic radiation especially in this area before the K-Pg boundary extinction event.