Shell oval-lenticular, white, fragile and not translucent, with an erect vertical apex. Protoconch with 2 or al¬most 2 whorls. The nucleus and at least the first half whorl of the protoconch are smooth; later with five very fine, occasionally undulating spiral threads and, especially at its end, with fine interconnecting lines forming a net-like pattern. The colour of the protoconch is cream with light brown at the borders. Teleoconch with about 1,75 whorls, with rapid development; it is sculptured by many fine axial ribs which are slightly curved, numbering about 13 on the first half whorl, 45-55 on the second half and from 90 to 110 on the body whorl, with very small spaces between them. With many fine spiral striae throughout, evident in the spaces between the ribs. Aperture ovoid, with the outer lip sharp, only contacting the penultimate whorl for a short distance. An open umbilicus without any keel shows the previous whorls. Dimensions: From 1.7 to 2.3 mm in diameter.

The shells of the species of Macromphalina from the area of study that are similar in appearance can be differentiated from M. paradoxa: all of them have protoconchs of less than 2 whorls; furthermore, M. robertsoni has a protoconch with the spiral threads beginning on the nucleus; M. garcesi has microtubercles on the nucleus and first whorl of the protoconch, the threads are finer and, on the teleoconch, the number of axial ribs is smaller. M. palmalitoris has the spiral threads of the protoconch finer and more simple, and on the teleoconch the axial and spiral sculpture is stronger and less crowded. M. jibacoa has more irregular sculpture. Other species have much stronger cords on the protoconch.Shell and protoconch of the present species are clearly distinct from those of the genus Megalomphalus.

Only known from Cienfuegos, south Cuba.