Othnielia is a genus of hypsilophodont dinosaur from the Oxfordian-Tithonian age of the Late Jurassic Period. Several remains have been discovered in the Morrison Formation in the North American states of Wyoming, Utah and Colorado. But, according to revisions made on Morrison ornithischians, the only definite remains are that of a femur belonging to the type species Othnielia rex, named by Peter Galton in 1977.
Othnielia was named for its original describer, famed 19th century paleontologist Othniel Charles Marsh, who originally named it Nanosaurus rex. It was relatively small for a dinosaur. The adult was between 4.9 and 6.6 feet long and weighed about 22 pounds. It was an agile bipedal herbivore with small arms and long legs. Although this animal was portrayed as a tree-climbing dinosaur in the novel Jurassic Park, there is no evidence to make that conclusion in mainstream science.
In Peter Galton’s paper on the Othnielia, only the holotype and two partial skeletons were included. The remainder of several discoveries were left out due to inadequate placement claims in the genus. Excluded from the paper is a nearly complete specimen that is housed in the Aathal Museum nicknamed “Barbara” and some other juvenile remains, which some notable paleontologists place in the Othnielia rex species. Another specimen designated as Othnielia is on display at the Denver Museum of Nature and Science.