Pacifastacus is a genus of crayfish native to western North America, containing the following six species (DD = Data Deficient; CR = Critically Endangered; LC = Least Concern; EX = Extinct):Pacifastacus chenoderma (fossil: Miocene – Pliocene)Pacifastacus connectens DDPacifastacus fortis CR – shasta crayfishPacifastacus gambelii LCPacifastacus leniusculus LC – signal crayfishPacifastacus nigrescens EX↑ ↑