Cooke (1959) erected this genus on account of its greatly reduced phyllodes. All other characters present in the type species of this genus are typical of Plagiochasma.
C. W. Cooke. 1959. Cenozoic echinoids of eastern United States. United States Geological Survey, Professional Paper, 321, 106 pp., 43 pls.
J. W. M. Jagt. 2000. Late Cretaceous-Early Paleogene echinoderms and the K/T boundary in the southeast Netherlands and northeast Belgium - Part 4: Echinoids, Scripta Geologica, 121, 352-353.
P. M. Kier. 1962. Revision of the cassiduloid echinoids. Smithsonian Miscellaneous Collections, 144 (3) 262 pp.
A. B. Smith & C. H. Jeffery. 2000. Maastrichtian and Paleocene echinoids: a key to world faunas. Special Papers in Palaeontology, 63, 406 pp.