Procambarus clarkii
The Ash Meadows killifish ("Empetrichthys merriami") is a species of killifish from the subfamily Empetrichthyinae, part of the family Goodeidae, which was first documented by C. H. Gilbert in 1893 and historically occupied numerous springs near Ash Meadows, Nye County, Nevada, United States. This species was last seen in 1948 and is believed to have gone extinct in the early 1950s, likely as a result of habitat alteration and competition with and predation by introduced crayfish "Procambarus clarkii", mosquitofish ("Gambusia affinis"), black mollies ("Poecilia sphenops"), and bullfrogs ("Rana catesbeiana").