Medusafissurella is closely associated with
Amblychilepas and
Dendrofissurella with which it shares
radular and
shell characters. But
Medusafissurella has a smaller body than the species in
Amblychilepas, the genus to which it was previously assigned. The body of species in
Medusafissurella is larger than the shell. The anterior part of the shell is raised but is markedly narrowed. This character distinguishes
Medusafissurella from most species in the genus
Fissurella. The edge of the anterior shell is thinner and sharper than in the rest of the shell. The posterior end of the shell is not raised at all or only slightly raised. The opening at the apex (
foramen) has an oval shape. The
sculpture of the shell shows strong, scabrous ribs (= transverse folds) giving the impression of a rough surface with minute ribs. This character sets
Medusafissurella apart from
Amblychilepas and
Dendrofissurella The posterior portion of the foot is covered by the shell. The
mantle folds only slightly envelop the edge of the shell. The foot also shows elaborate
propodial processes at the
propodium (front part of the foot) with numerous subequal (= nearly equal) radiating tentacles, that are sometimes branched, while in
Dendrofissurella the tentacles have a single, main branching structure. The function of these tentacles is not well understood. They may serve to trap or hold food, but then they would be better attached to the snout above them instead of being attached to the propodium. The large outer lateral tooth of the
radula is quadricuspid ( = with four cusps). The eyes are situated at the base of the cephalic tentacles. ==Species==