Cenomanian “orbitoliniform” foraminifera—State of the art and description of Ebrahimiella dercourti (Decrouez and Moullade, 1974) gen. et comb. nov. (family Coskinolinidae) from the Sarvak Formation (SW Iran, Zagros Zone)

Abstract

From surface and subsurface sections of the middle Cenomanian Sarvak Formation of SW Iran (Zagros Zone), specimens of “Valdanchella” dercourti Decrouez and Moullade were recovered. With the occurrence of a pseudo-keriothecal wall structure, a large subapical embryo and the lack of horizontal partitions, this taxon can be assigned neither to the late Berriasian–Valanginian Valdanchella Canerot and Moullade nor to any other known genus. Therefore, the genus Ebrahimiella is established with the new combination E. dercourti (Decrouez and Moullade) and assigned to the family Coskinolinidae. Orbitoliniform larger benthic foraminifera evidenced a distinct radiation, in Cenomanian shallow-water carbonates of the former southern Neotethyan margin, especially the Arabian Plate, including also endemic forms. Whereas the lower (p.p. middle?) Cenomanian exhibits the dominance of Orbitolininae (genera Orbitolina, Mesorbitolina, Conicorbitolina), the middle Cenomanian documents the appearance of new taxa of the Dictyoconinae (e.g. Persiconus sarvaki Yazdi-Moghadam and Schlagintweit). An updated inventory of Cenomanian orbitoliniform taxa with stratigraphic ranges is provided.