Monolophosaurus actually an interesting subject to convergent evolution. A peak at the top of his head, like that of Coelophysids crested. Monolophosaurus peak, however, is different in that it is hollow, like the top Lambeosaurine. Hollow in the top of the channel causes the nasal cavity, suggesting Monolophosaurus can sing through his peak, again as Lambeosaurines.
Monolophosaurus discovered in 1994 by paleontologist Currie & Zhao, initially only the head and neck were found. There was also the discovery of the fossil pelvis at a later date in Thailand. It is sometimes considered that Monolophosaurus associated with Allosaurids, although there is little evidence to support a connection to the family, besides the obvious theropod.
Monolophosaurus lived in China during the Jurassic period, the skull was found to have an indication of pre-mortem water. It is used as evidence to support the theory that the dinosaurs Monolophosaurus is partially water, using a peak like Parasaurolophus considered when first discovered.