Allosaurus

dinosaur · predator · Jurassic

Different lizard. The name Allosaurus means 'different lizard,' because scientist Othniel Marsh thought its lightweight backbones were unlike any other dinosaur's.

Jurassic giant. Allosaurus lived between 155 and 143 million years ago, during the late Jurassic period.

Discovered in 1877. The first fossils clearly belonging to this dinosaur were described by Marsh in 1877.

Found far and wide. Most Allosaurus fossils come from North America's Morrison Formation, but some have also turned up in Portugal.

A name comeback. For much of the 1900s it was called Antrodemus, until lots of fossils from the Cleveland-Lloyd Quarry brought back the name Allosaurus.