As with other eldonioids, it was originally thought to have been pelagic, but is now thought to be benthic.[4]
In addition to the type species R. grandis, two other Rotadiscus species have been proposed. The first is known only from one complete juvenile specimen and a few fragments, and was originally described as "Brzechowia sp." It remains without a formal species name, but has been transferred to Rotadiscus.[5] The species initially described as R. guizhouensis has since been reassigned to the genus Pararotadiscus.[2]
A 2023 cladistic analysis based on new fossils places Rotadiscus, along with other eldonioids, as stem-group ambulacrarians in the clade Cambroernida.[6]