Paropsonema
Paropsonema is an eldonioid known from the Devonian of upstate New York and the Silurian of southern Australia. It is the latest-surviving known member of the Eldonioidea and Cambroernida.
A specimen described in 2018 may represent an additional species, but has been tentatively assigned to P. cryptohya; it represents the youngest described paropsonemid.
The species Discophyllum mirabile has been thought to be closer to Paropsonema than to the sole previously-described species of Discophyllum, D. peltata. As a result, sources treat it as Paropsonema mirabile. Conversely, at least one worker has treated P. cryptophya as a member of Discophyllum, D. cryptophya, although this has not been followed by later authors. Regardless, Paropsonema and Discophyllum are grouped together informally as "paropsonemids."