Hmmm... that's alot of trouble to go to for display. Seems like they
would just have evolved bright colors adn funny horns for that.
Theropods probably did evolve funny horns for display. At least that's one
explanation behind the development of the sometimes bizarre cranial
ornamentation of many theropods - like _Dilophosaurus_, _Majungatholus_,
_Cryolophosaurus_, _Baryonyx_, _Monolophosaurus_, and even the more subdued
cranial structures of _Zupaysaurus_, _Allosaurus_ and_Tyrannosaurus_
Having said that, "display" is too often used as a default function for
structures that have no other obvious function, like attack or defense.
Nevertheless, evidence of sexual dimorphism in these structures may indicate
a role in sexual or territorial display.
Interestingly (maybe), coelurosaurs rarely show cranial ornamentation.
Perhaps the plumage (especially pennaceous feathers) replaced cranial crests
or horns as the principal medium for sexual or territorial signalling