Nummulites crassichordatus n.sp. (N. laevigatus group, Foraminifera) from the Middle Eocene of the Citadel section, Gebel Mokattam, Egypt

Abstract

The Middle Eocene larger foraminifera of the Mokattam Formation corpping out at the Citadel section, north of Gebel Mokattam, were studied. The Mokattam Formation has yielded Nummulites crassichordatus n. sp. kwhich belongs to the Nummulites laevigatus group. In addition Nummulites lyelli morphotype 1 and Nummulites lyelli morphotype 2 are nominated according to the nature of septa and also described and both belong to Nummulites lyelli subgroup, Boukhary & Kamal, 2003. These morphotypes : Nummulites lyelli morphotype 1 is comparable with Nummulites gizehensis, ontogeny of which grades from lax to tight (like that of Nummulites gizehensis). Also Nummulites lyelli morphotype 2 is comparable with Nummulites lyelli s.str., that its ontogeny grades from tight to lax (like that of Nummulites lyelli). These two morphotypes 1&2 exist at the bottom and the top of Nummulites praelyelli bank