Skeleton of Eryops. Eryops, meaning "drawn-out face" because most of its skull was in front of its eyes, is a genus of extinct, semi-aquatic amphibian found primarily in the Lower Permian-aged Admiral Formation (about 295 million years ago) of Archer County, Texas. Eryops averaged a little over 1.5-2.0 meters (5-6 ft) long, making it one of the largest land animals of its time. It weighed about 90 kilograms (200 lb). Eryops is an example of an animal that made successful adaptations in the movement from a water environment to a terrestrial one. Royal Tyrrell Museum, Drumheller, Alberta, Canada.