Faxonius peruncus

Faxonius peruncus, the Big Creek crayfish, is a species of crayfish in the family Cambaridae. It is endemic to Missouri. The common name refers to Big Creek, where the original specimens were found.

Distribution
F. peruncus is limited to the St. Francis River watershed.

Threats
The main threat to this species is a related species, F. hylas which was introduced into the area in 1984. F. hylas out-competes, and hybridises with, F. peruncus. Also, pollution from the Southeast Missouri Lead District affects the water quality in the local area.