You searched for: “haplocanthosauria
Haplocanthosaurus (s) (noun), Haplocanthosauria (pl)
A "single-spined (simple-spined) lizard" from Late Jurassic Colorado, Wyoming, and Utah, USA. This creature was formerly known as Haplocanthus. It was found by paleontologist John Bell Hatcher in 1901 and named by him in 1903.