Shell rounded, slightly depressed, white, with the protoconch a little prominent. Protoconch of one whorl which begins with a nucleus of about 0. 1 mm and a first half whorl that appear smooth, but in fresh specimens can be seen to be irregularly roughened. Subsequently there are about 12-13 irregular spiral lines; in some places they are interrupted and in other have prominences. Beached shells have a smooth protoconch with the spiral lines almost absent. The protoconch has a translucent brown colour. This brown colour of the protoconch is very constant, even in very eroded shells. The teleoconch has between 2,25 and 2,5 whorls. They have fine and slightly oblique axial ribs which initially are a little more separated, with very fine spiral striations in the interspaces. The number of the axial ribs on the first whorl ranges from 24 to 30. These ribs are also present on the second whorl, later almost disappearing on some of the largest shells, but remaining visible near the suture. On these shells the rest of the surface of the shell shows only fine, undulating spiral striae, crossed by irregular and crowded growth lines. The aperture is pyriform, with an extension in the upper part forming the only point of contact with the previous whorl. The umbilicus is wide and deep, with axial lamellae, but never a visible peripheral keel. Dimensions: maximum size of the largest shells is 5.5 mm in width and 4.5 mm in height.

Placement of this species in Macromphalina and not in Megalomphalus may be only a provisional option, because it seems to be in an intermediate situation. Future study of the soft parts and radula could confirm or change the actual placement. M. redferni is differentiated from most of the species of the genus Macromphalina in this area by its more elevated form and the 12-13 spiral lines on its protoconch; furthermore, most of the species of Macromphalina have a white protoconch. In the genus Megalomphalus, M. oxychone and M. pilsbryi differ by having umbilical keels. M. millerae has a white protoconch, which also has fewer spiral cords; M. lamellosus is close but it also has a white protoconch with fewer spiral cords.

Only known from the Bahama Islands, as the shells from Panama are dubious, and it will be necessary to examine better material to confirm their identity.