|Distribution||Miocene (Langhian), Austria.|
|Type||Retzneiosoma jaseneki Kroh, 2005, p. 16|
|Species Included||Only the type species|
|Classification and/or Status||Euechinoidea, Echinothurioida, Echinothuriidae
|Remarks||The distinct crenulation of tubercles in this genus separates it from all echinothurioids other than Kamptosoma and occasionally in some species of Asthenosoma. The distinct membranous gaps between plates of the test place this taxon in the Echinothuriidae. However, as well as its crenulate tubercles, it differs from Araeosoma by having much less pronounced membranous gaps between its plates, and denser tuberculation. Asthenosoma differs in lacking primary tubercles on its aboral plates. Calveriosoma lacks membranous gaps from its aboral surface and has primary tubercles on only every second or third ambulacral plate. Hapalosoma is morphologically the closest but its demiplates are adradial in position in the adapical part of the test.
Kroh, A. 2005. Catalogus fossilium Austriae. Band 2 Echinoidea neogenica. Verlag der Osterreischen Akademie der Wissenschaften, Wien. 1210 pp, 82 pls.