Stegosaurus

The Stegosaurus (known as the Stegosaur in and ) is a three-part fossil in the  introduced in  that appears in all subsequent games.

In
When donating the final part to Blathers in, he will provide the following information about the fossil:

In
When donating to Blathers in, he will provide the following information about the fossil:

The Stegosaur can be found in the second room of the fossil exhibit in the museum.

In
When donating the final part to Blathers in, he will provide the following information about the fossil:

The Stegosaur can be found in the first room of the fossil exhibit in the museum.

In
After donating the final part of the fossil in, its plaque in the museum will read:

"The name stegosaurus literally means "roofed lizard" or "covered lizard." This name came from a belief at the time of discovery that it was covered in bony plates like a shell. We now know that the plates stood fully upright along its back and were covered in thick skin. Beyond protection from harm, they were likely used to regulate body temperature."

The Stegosaurus can be found in the first room of the fossil exhibit in the museum.

Real-world information
Stegosaurus is a genus of herbivorous dinosaur. It lived in the Late Jurassic, 155 to 150 million years ago. They lived mostly in what is now the western United States, although one fragmentary specimen is known from Portugal. They could reach 9 meters in length and weigh 5.3-7 tons. Based on the locations of their fossils, Stegosaurus likely preferred drier climates than many of its contemporaries, such as Diplodocus, Apatosaurus, and Allosaurus.

Along with Ankylosaurus, they are classified in the clade Thyreophora, a group of armored ornithischian dinosaurs. Stegosaurians are known for their modified osteoderms which grow along the back of the animals. Stegosaurus in particular has exceptionally large, plate-like osteoderms, unlike its more spiky relatives. It also has four spikes (arranged in two pairs) on its tail, in what is known as a "thagomizer". Stegosaurus likely used its thagomizer for defense, as some specimens of Allosaurus, the apex predator of the time, show wounds on their tails that match the shape of a thagomizer.