What is "aenigmastacus"

Aenigmastacus crandalli is a species of fossil freshwater crayfish. It was found in Eocene lake deposits in British Columbia, and was described in 2011. It is the first member of the Gondwana-distributed family Parastacidae to be found in the Northern Hemisphere, and is the only species in the genus Aenigmastacus. Twelve specimens are known, with a total body length of . On some specimens, details of the internal anatomy can be seen due to the exceptional preservation.