In an attempt to interpret the restricted occurrence
of the large Permian Omphalonema grandiosum, Pan
& Yu (1993) suggested that gigantism in freshwater
gastropod may herald the extinction of the respective
clade. Macromargarya aliena has been recorded from
a single level of the short section at Santang. Whether
it occurs in additional horizons of the Gongkang
Formation has to be checked. As a result, it remains
elusive whether M. aliena was a terminal member of
an evolutionary lineage or rather a short-lived offshoot
derived from a Margarya-like ancestor. The closely
related genus Margarya persists until today in the
lakes of Yunnan – although it may soon become extinct
due to human impact.