Holotype . Specimen MB.C.!()35.1, figured by Korn et al., 2010 in Fig. 29A.

2010. Helicocyclus inornatus. - Korn, Bockwinkel & Ebbighausen, p. 70, Figs. 29-30, measurements in Tables 41-42.

H. inornatus belongs to the group within the genus Helicocyclus lacking ribs. It is similar to H. fuscus,

but that species has weaker constrictions not directed forward. H. laxaris has a stouter shell with a narrower umbilicus .