Remarks: Margarya nanningensis resembles the type species
of the genus, M. melanioides Nevill, 1877 (Fig. 3B,
C) both with regard to general shell shape and ornamentation,
but is stouter and has a significantly shorter spire. M.
nanningensis is ornamented with two major spiral carinae
carrying spines, the most prominent one being the one on
the shoulder. In contrast, M. melanioides has a single dominant
carina, carrying a row of spines or nodes, at about mid
height of the whorls; this major carina may be accompanied
by two or more subordinate, smooth or nodose carinae. As
a result, M. melanoides lacks the angular, step-shaped outline
seen in M. nanningensis, and has a more oval, slightly
tear-shaped aperture (Fig. 3B). Moreover, M. nanningensis
is distinctly larger than all other species of Margarya.