New Cenomanian "nummoloculinas" of the Natih Formation of Oman

Abstract

Two new genera and species of "nummoloculinas", Planinummoloculina gnosi gen. et sp. nov. and Nummoloculinodonta akhdarensis gen. et sp. nov., are described from the lower-middle Cenomanian of Oman. They are compared with other "nummoloculinas" known from the Albian to Maastrichtian of the Tethys. The mode of coiling, the number of chamber per whorl and the type of the aperture are the main distinctive criteria to separate them. Planinummoloculina gnosi gen. et sp. nov. seem to be stratigraphically and geographically very restricted, and shows very low intraspecific morphologic variability. Nummoloculinodonta akhdarensis gen. et sp. nov. is more widespread both vertically and horizontally, and shows a higher intraspecific morphologic variability.

Two new genera and species of "nummoloculinas", Planinummoloculina gnosi gen. et sp. nov. and Nummoloculinodonta akhdarensis gen. et sp. nov., are described from the lower-middle Cenomanian of Oman. They are compared with other "nummoloculinas" known from the Albian to Maastrichtian of the Tethys. The mode of coiling, the number of chamber per whorl and the type of the aperture are the main distinctive criteria to separate them. Planinummoloculina gnosi gen. et sp. nov. seem to be stratigraphically and geographically very restricted, and shows very low intraspecific morphologic variability. Nummoloculinodonta akhdarensis gen. et sp. nov. is more widespread both vertically and horizontally, and shows a higher intraspecific morphologic variability.

Two new genera and species of "nummoloculinas", Planinummoloculina gnosi gen. et sp. nov. and Nummoloculinodonta akhdarensis gen. et sp. nov., are described from the lower-middle Cenomanian of Oman. They are compared with other "nummoloculinas" known from the Albian to Maastrichtian of the Tethys. The mode of coiling, the number of chamber per whorl and the type of the aperture are the main distinctive criteria to separate them. Planinummoloculina gnosi gen. et sp. nov. seem to be stratigraphically and geographically very restricted, and shows very low intraspecific morphologic variability. Nummoloculinodonta akhdarensis gen. et sp. nov. is more widespread both vertically and horizontally, and shows a higher intraspecific morphologic variability.