Perhaps the second most famous carnosaur after Tyrannosaurus Rex, the Allosaurus was a powerful carnivorous theropod that lived during the late Jurassic period.
Allosaurus was known for many years under the name Antrodemus, because it was first categorized by O.C. Marsh under that name. However, as with many discoveries from this competitive period of paleontology, there were profound issues with the verifiability of the discovery. In the latter half of the 20th century, it became preferable to refer to Allosaurus rather than Antrodemus, because that was the name assigned to the first well-documented discoveries.
Allosaurus is frequently depicted in art as having longer forelimbs than the Tyrannosaurus Rex, with three fingers instead of two. It is also known to be somewhat smaller, with the largest specimen reaching 32 feet in length.