Amurosaurus or “Amur lizard” is a genus of dinosaur of the Late Cretaceous Period which thrived in what is now eastern Asia. It was first described in 1991 by Russian paleontologists Yuri Bolotsky and Sergei Kurzanov. Its name is derived from the Amur River and the Greek word sauros (lizard). The Amur River forms the border of Russia and China and is near where the remains of Amurosaurus was discovered. There is one known species (A. riabinini) named in honor of the late Russian paleontologist Anatoly Riabinin, who led the first expeditions to recover dinosaur remains in the Amur region in 1916.
Amurosaurus was a bipedal (walked on two feet) herbivore with a duckbill shaped snout. Scientists have spectulated that it may have had a hollow crest on top of its head. Though only a few fossils have been recovered, it is believed that the specimen was about 20 feet long. All recovered fossils have come from one bone bed, discovered in 1984 within the city limits of Blagoveschensk in far eastern Russia. The bone bed is found in the Udurchukan Formation, the oldest geologic formation in far eastern Russia and northern China. Only a fraction of the bone bed has been uncovered, but at least 90% of the remains found are of lambeosaurine dinosaurs like Amurosaurus. Most of the specimens recovered were of juveniles.
The original specimen collected consists of only a maxilla and dentary (upper and lower jaw bone, respectively). However, most of the other bones of the skull and skeleton have also been preserved in the bed, albeit from many different individuals. The abundance of skeletal remains makes the Amurosaurus the most completely known Russian dinosaur. One piece of evidence missing from the remains of the Amurosaurus is the crest. Most other known lambeosaurines have a hollow crest on top of their skulls, and although no crests have been found in the bone beds around the remains of this dinosaur, the bones of the roof of the skull are modified to support one, so it is generally assumed that Amurosaurus was crested as well.