Family Eruciidae Burr 1899 (grasshopper)
Insecta - Orthoptera - Eruciidae
Parent taxon: Eumastacoidea according to D. K. M. Kevan and D. C. Wighton 1981
Sister taxa: Episactidae, Eumastacidae, Promastacidae
Subtaxa: Erucius
Ecology: fast-moving ground dwelling grazer-herbivore
Distribution: found only at Ruby River, between Peterson and Morman Creeks (Oligocene of Montana)