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'''Procheneosaurus''' (meaning "before the goose lizard [''Cheneosaurus'']") was the name given to a genus of hadrosaur dinosaur, based on small skulls with low domes in front of the eyes. It is now believed that the remains referred to its various species were from juvenile individuals of multiple dinosaur genera. Peter Dodson's 1975 work first broke them down among ''Corythosaurus'' and ''Lambeosaurus'', Taxonomic implications of relative growth in lambeosaurine dinosaurs, , Peter, Dodson, Systematic Zoology, 1975 but later work indicates ''Hypacrosaurus'' was included as well. Dinosaur Eggs and Babies, , John R., Horner, Cambridge University Press, 1994, The name ''Procheneosaurus'' is thus invalid. Five species have been assigned to it at one time or another: ''P. praeceps'', ''P. altidens'', ''P. cranibrevis'', and ''P. erectofrons'', all from North America; and ''P. convincens'', from Asia.
The genus was created by Matthew in 1920 in a photo caption for a skeleton and skull from the late Campanian-age Upper Cretaceous Two Medicine Formation of Montana, USA. Canadian dinosaurs, , William Diller, Matthew, Natural History, 1920 This is normally not considered to be sufficient for publication, and the specimen was later included in ''Tetragonosaurus''. However, Richard Swann Lull requested that the latter name be suppressed in favor of ''Procheneosaurus'', which was granted. The type species, ''Procheneosaurus praeceps'', was described by Parks in 1931 for a skull from the Dinosaur Park Formation of Alberta, Canada, as a species of ''Tetragonosaurus''. A new genus and two new species of trachodont dinosaurs from the Belly River Formation of Alberta, , William A., Parks, University of Toronto Studies, Geological Series, 1931 This species is now considered to be a specimen of ''Lambeosaurus lambei'', although ''Procheneosaurus'' predates ''Lambeosaurus'', and therefore would need to be suppressed to continue to use the well-known name ''Lambeosaurus''. ''P. altidens'', also from the Dinosaur Park Formation, was a new combination erected by Lull and Wright in 1942 for "Trachodon" ''altidens'', Hadrosaurian Dinosaurs of North America, , Richard Swann, Lull, Geological Society of America, 1942, and may also be a specimen of ''Lambeosaurus'', although it is based on only a maxilla, so it is difficult to be certain.
''P. cranibrevis'', from the Dinosaur Park Formation and named as a species of ''Tetragonosaurus'' in 1935 by Charles M. Sternberg, was slightly larger than the other species, Hooded hadrosaurs of the Belly River Series of the Upper Cretaceous, , Charles M., Sternberg, Canada Department of Mines Bulletin (Geological Series), 1935 and was interpreted by Dodson as a juvenile ''Corythosaurus''. Further study has shown that the type specimen is a ''Lambeosaurus'' juvenile, based on how the skull bones articulate, and that several other specimens assigned to it are ''Corythosaurus''. Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed, , David C., Evans, Indiana University Press, 2005, ''P. erectofrons'', named by Parks as a species of ''Tetragonosaurus'', is based on a skull from the Dinosaur Park Formation. He assigned Matthew's skeleton to it as well. Dodson found it to be a juvenile ''Corythosaurus casuarius'', although Matthew's distinct Two Medicine Formation skeleton appears to belong to a young ''Hypacrosaurus stebingeri''.
''P. convincens'', from the Late Cretaceous of Kazakhstan, is known from a nearly complete skeleton missing only the snout and end of the tail. It was named by A. K. Rozhdestvensky in 1968. Upper Paleozoic and Mesozoic Amphibians and Reptiles, , A.K., Rozhdestvensky, Akademia Naul SSSR, 1968, It may be synonymous with ''Jaxartosaurus aralensis'', The Dinosauria, , John R., Horner, University of California Press, 2004, or it could be its own genus, The Age of Dinosaurs in Russia and Mongolia, , David B., Norman, Cambridge University Press, 2000, which would require a new generic name.

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★ ''Procheneosaurus'' in The Dinosaur Encyclopaedia at Dino Russ's Lair