Perhaps the oldest remains of Protosphyraena in North America have come from the upper beds of the Dakota Sandstone (middle Cenomanian) in Russell County, Kansas (Everhart, 2005; p. 91).
The discovery of Protosphyraena fossils in North America may date back to the earliest times, with evidence found in the upper layers of the Dakota Sandstone, specifically in Russell County, Kansas, as documented by Everhart (2005; p. 91).