Parasaurolophus

Parasaurolophus (pronounced /ˌpærəsɔːˈrɒləfəs/ parr-ə-saw-rol-ə-fəs, commonly also /ˌpærəˌsɔrəˈloʊfəs/ parr-ə-sawr-ə-loh-fəs; meaning "near crested lizard" in reference to Saurolophus) was a genus of ornithopod dinosaur from the Late Cretaceous Period of what is now North America, about 76.5–73 million years ago.^[1] It was an herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri (the type species), P. tubicen, and the short-crested P. cyrtocristatus. Remains are known from Alberta (Canada), and New Mexico and Utah (USA). It was first described in 1922 by William Parks from a skull and partial skeleton in Alberta.

Parasaurolophus was a hadrosaurid, part of a diverse family of Cretaceous dinosaurs known for their range of bizarre head adornments. This genus is known for its large, elaborate cranial crest, which at its largest forms a long curved tube projecting upwards and back from the skull. Charonosaurus from China, which may have been its closest relative, had a similar skull and potentially a similar crest. The crest has been much discussed by scientists; the consensus is that major functions included visual recognition of both species and sex, acoustic resonance, and thermoregulation. It is one of the rarer hadrosaurids, known from only a handful of good specimens.

http://en.wikipedia.org/wiki/Parasaurolophus