The fossils of Eoprephasma were deposited to the Thompson Rivers University and Burke Museum of Natural History and Culture while a study on Eoprephasma was published in the journal Canadian Entomology.
The three Susumanioidea fossils, part/counterpart F-846 and F-951 plus F-1392 and F-1393 are deposited in the Thompson Rivers University. Along with other well preserved insect fossils, the Eoprephasma specimens were collected from layers of Ypresian age Lagerstatte lake sediments Washington, USA, and an additional three partial Susumanioidea fossils were recovered from British Columbia, Canada. The counterpart specimen F-1099 is also in the Thompson Rivers University collections, while the part side, PB-3825 is at the Burke Museum of Natural History and Culture. 
