Holotype. Specimen MB.C.19036.1, figured by Korn et al., 2010 in Fig. 31A.

2010Korn, Bockwinkel, Ebbighausen, p. 71, Figs. 31, 32, measurements in Tables 43-45.

H. laxaris has a much stouter shell than H. laxaris and H. fuscus.