Pacifastacus is a genus of crayfish native to western North America (USA and Canada), containing six species, two of which are extinct: †Pacifastacus chenoderma (fossil: Miocene – Pliocene) Pacifastacus connectens Pacifastacus fortis – Shasta crayfish Pacifastacus gambelii Pacifastacus leniusculus – signal crayfish †Pacifastacus nigrescens – Sooty crayfish References Astacidae Crustacean genera