P. willybemisi is known a nearly complete specimen from the Tanis locality of the Hell Creek Formation in North Dakota, USA, which dates to the late Maastrichtian stage of the Late Cretaceous, approximately 66 million years ago.

The type species, P. willybemisi, is named in honor of William E. Bemis, a professor of ecology and evolutionary biology and curator of fishes at Cornell University,[2] who has conducted extensive research on paddlefish.

The species is placed in the clade Polyodonti, which includes all polyodontids other than the most primitive genus Protopsephurus.

Like Psephurus and other extinct paddlefish genera, the genus was likely piscivorous, feeding on fish, rather than planktivorous like Polyodon.

This order Acipenseriformes (Sturgeon and Paddlefish) related article is a stub.