It's been a while since I made the lineup of the Saurolophinae. So here's a lineup of Iguanodontids and primitive Hadrosauroids. Originally I wanted to add some others too, like Camptosaurus, Probactrosaurus and Bactrosaurus. But I couldn't find any good reference for those.
I've based these reconstructions on lateral views of photo's or scientific drawings of the skulls.
The names are as follows:
Iguanodon bernissartensis - Altirhinus kurzanovi
Mantellisaurus atherfieldensis - Equijubus normani
Dryosaurus altus - Tethyshadros insularis
Ouranosaurus nigeriensis - Eolambia caroljonesa
Not to scale