The holotype and only known specimen of Stegomosuchus (AM 900[REF]) was discovered at what was then known as the Hines Quarry, east of East Longmeadow, Massachusetts, just before the turn of the 20th century.
Its discoverer, G. B. Robinson, took home the blocks containing the specimen and placed them in his door yard, where they were exposed to the elements for "about seven years."