[1] The specimens were collected from a sandstone outcrop of the Hell Creek Formation 24 miles (39 km) southeast of Fort Peck, Montana by a University of Michigan Museum of Paleontology expedition in 1938. the fossils were in close association with the holotype specimen of the extinct sturgeon Protoscaphirhynchus squamosus.

[1] The Paleopsephurus specimens were first studied by American paleontologist and ichthyologist Archie Justus MacAlpin.

He published his detailed 1947 type description in the journal Contributions from the Museum of Paleontology, University of Michigan.

The stellate bones are loosely packed and more poorly developed compared to the ones in Crossopholis or Polyodon, but are similar to those of Psephurus.

[3] Paleopsephurus exhibits a combination of characters which suggests that it is more derived than Protopsephurus, but is more basal than Crossopholis, Polyodon, or Psephurus.