The current status and habitats of the Illinois Cave amphipod, Gammarus acherondytes hubricht and mackin (crustacea: Amphipoda)

Gammarus acherondytes is a rare amphipod endemic to Illinois subterranean streams. It previously was recorded from five cave streams in Monroe and St. Clair counties, Illinois. An examination of 164 caves from 1986 to 1995 produced only one new record, Madonnaville Cave, in Monroe County. These recent collections have documented a large population of G. acherondytes in Illinois Caverns, a moderate-sized population in Fogelpole Cave, and a small population in Krueger-Dry Run Cave. Pautler Cave, a previously known locality, has been bulldozed shut by the landowner. No specimens of G. acherondytes have been collected in Stemler Cave since 1965, and no specimens were collected in Madonnaville Cave in 1995 although a single specimen was collected in 1986.