Marmorkrebs, or marbled crayfish, are parthenogenetic crayfish that were discovered in the pet trade in Germany in the 1990s. Procambarus fallax forma virginalis is an informal subspecies designation for marmorkrebs, and some researchers have proposed a new species designation, Procambarus virginalis. Marmorkrebs are closely related to the "slough crayfish", Procambarus fallax. P. fallax is widely distributed across Florida, but no natural populations of marmorkrebs are known. Information provided by one of the original pet traders as to where the marmorkrebs originated was deemed "totally confusing and unreliable". Marmorkrebs is German for "marbled crayfish".