Stegosaurus

Stegosaurus is a type of armored dinosaur. Their fossil bones have been found in rocks dated to the Late Jurassicperiod (Kimmeridgian to early Tithonian ages), between 155 and 150 million years ago, in the western United States and Portugal. Several species have been classified in the upper Morrison Formation of the western U.S, though only three are universally recognized; S. stenops, S. ungulatus and S. sulcatus. The remains of over 80 individual animals of this genus have been found.[2]Stegosaurus would have lived alongside dinosaurs such as Apatosaurus, Diplodocus, Brachiosaurus, Allosaurus and Ceratosaurus; the latter two may have been predators of it.

Description
The quadrupedal Stegosaurus is one of the most easily identifiable dinosaur genera, due to the distinctive double row of kite-shaped plates rising vertically along the rounded back and the two pairs of long spikes extending horizontally near the end of the tail. Although large individuals could grow up to 9 m (29.5 ft) in length, the various species of Stegosaurus were dwarfed by their contemporaries, the giantsauropods. Some form of armor appears to have been necessary, as Stegosaurus species coexisted with large predatory theropod dinosaurs, such as Allosaurus and Ceratosaurus.

Most of the information known about Stegosaurus comes from the remains of mature animals; more recently, though, juvenile remains ofStegosaurus have been found. One subadult specimen, discovered in 1994 in Wyoming, is 4.6 m (15.1 ft) long and 2 m (6.6 ft) high, and is estimated to have weighed 2.4 metric tons (2.6 short tons) while alive.