Olorotitan was a genus of lambeosaurine duckbilled dinosaur from the middle or latest Maastrichtian-age Late Cretaceous, whose remains were found in the Tsagayan Formation beds of Kundur, Amur Region, Far Eastern Russia. The type, and only species is Olorotitan arharensis whose holotype specimen, consisting of a nearly complete skeleton, was described by Pascal Godefroit et al. in mid-2003. The generic name Olorotitan means “gigantic swan”, while the specific descriptor arharensis refers to the location of the fossil find at Arhara County. Olorotitan is distinct from other crested duckbills by its possession of an unusual crest that points backward and takes on a hatchet or fan-like shape. Its discovery has implications for the diversity of lambeosaurine hadrosaurids.
Hadrosaurs have a long association with North America, but they are known from other areas like Asia where they are usually represented by incomplete remains. Olorotitan however was almost complete and became widespread through palaeontology circles as the most complete lambeosaurine hadrosaurid outside of North America. With eighteen vertebrae Olorotitan is also remarkable for having a very long neck for a hadrosaurid, and it was this neck length that was the inspiration for its name which means ‘giant swan’.
Olorotitan arharensis is based on the most complete lambeosaurine skeleton found outside North America to date. It was a large hadrosaurid, comparable to other large lambeosaurines like Parasaurolophus cyrtocristatus, and may have grown up to 8 meters (26 feet) long.
As a hadrosaurid, Olorotitan would have been a bipedal/quadrupedal herbivore, eating plants with a sophisticated skull that permitted a grinding motion analogous to chewing, and was furnished with hundreds of continually-replaced teeth. Its tall, broad hollow crest, formed out of expanded skull bones containing the nasal passages, probably functioned in identification by sight and sound.
The fact that Olorotitan exists in Asia at a time when other lambeosaurine hadrosaurids seem to have disappeared from North America suggests that the two continents were climatically different to one another, with a Asia having a more suitable habitat for lambeosaurines. A climatic difference could also explain why fossils of sauropods are also known from some areas of Asia long after they disappeared in North America.