Fissumella motolae n. gen. n. sp., a new soritoidean (Foraminifera) from the lowermost Albian carbonate platform facies of central and southern Italy

The Soritoidea (Foraminifera) represent an important component of Cenomanian microfossil assemblages of the central and southern Tethyan carbonate platforms and are widely used as biostratigraphic markers. In this paper a new taxon, Fissumella motolae n. gen. n. sp., is described from the Cretaceous carbonate platform facies of central and southern Italy. It is characterized by its small size, planispiral-involute arrangement of chambers, fissure-shaped single aperture and few and short radial septula subdividing the marginal lumen of the chambers. Fissumella motolae n. gen. n. sp. represents the first soritoidean in the fossil record showing internal subdivisions of the chamber lumen. Carbon isotope stratigraphy supports an earliest Albian age for this significant step in the evolution of the superfamily Soritoidea. The new subfamily Fissumellinae is established for soritoidean foraminifera with planispiral-involute lens-shaped shells, single aperture and chamber lumen subdivided by few and short septula.