Procheneosaurus

"Procheneosaurus" (meaning "before the goose lizard ["Cheneosaurus"] ") is a disused 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 genera of crested hadrosaurs. Peter Dodson's 1975 work first broke them down among "Corythosaurus" and "Lambeosaurus",cite journal |last=Dodson |first=Peter |authorlink=Peter Dodson |year=1975 |title=Taxonomic implications of relative growth in lambeosaurine dinosaurs |journal=Systematic Zoology |volume=24 |pages=37–54 |doi=10.2307/2412696 ] but later work indicates "Hypacrosaurus" was included as well.cite book |last=Horner |first=John R. |authorlink=Jack Horner (paleontologist) |coauthors=and Currie, Phillip J. |editor=Carpenter, Kenneth; Hirsch, Karl F.; and Horner, John R. (eds.)|title=Dinosaur Eggs and Babies |year=1994 |publisher=Cambridge University Press |location=Cambridge |isbn=0521567238 |pages=312-336 |chapter=Embryonic and neonatal morphology and ontogeny of a new species of "Hypacrosaurus" (Ornithischia, Lambeosauridae) from Montana and Alberta ] 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 coined by William Diller Matthew in 1920 in a photo caption for a skeleton and skull from the late Campanian-age Upper Cretaceous Dinosaur Park Formation of Alberta, Canada.cite journal |last=Matthew |first=William Diller |authorlink=William Diller Matthew |year=1920 |title=Canadian dinosaurs |journal=Natural History |volume=20 |issue=5 |pages=1–162 ] 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, but it was first coined as a species of "Tetragonosaurus". He also included in it Matthew's original specimen.cite journal |last=Parks |first=William A. |authorlink=William Parks |year=1931 |title=A new genus and two new species of trachodont dinosaurs from the Belly River Formation of Alberta |journal=University of Toronto Studies, Geological Series |volume=31 |pages=1–11 ] 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",cite book |last=Lull |first=Richard Swann |authorlink=R. S. Lull |coauthors= and Wright, Nelda E. |title=Hadrosaurian Dinosaurs of North America |year=1942 |publisher=Geological Society of America |series=Geological Society of America Special Paper 40 |pages=1-242 ] 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,cite journal |last=Sternberg |first=Charles M. |authorlink=Charles Mortram Sternberg |year=1935 |title=Hooded hadrosaurs of the Belly River Series of the Upper Cretaceous |journal=Canada Department of Mines Bulletin (Geological Series) |volume=77 |issue=52 |pages=1–37 ] 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".cite book |last=Evans |first=David C. |coauthors=Forster, Catherine F.; and Reisz, Robert R. |editors=Currie, Phillip J., and Koppelhus, Eva |title=Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed |chapter=The type specimen of "Tetragonosaurus erectofrons" (Ornithischia: Hadrosauridae) and the identification of juvenile lambeosaurines |year=2005 |publisher=Indiana University Press |location=Bloomington |pages=349-366 |isbn=0-253-34595-2 ] "P. erectofrons", named by Parks as a species of "Tetragonosaurus", is based on a skull from the Dinosaur Park Formation. Dodson found it to be a juvenile "Corythosaurus casuarius", although one distinct skeleton from the late Campanian-age Upper Cretaceous Two Medicine Formation of Montana, USA, 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.cite book |last=Rozhdestvensky |first=A.K. |authorlink=Anatoly Konstantinovich Rozhdestvensky |editor=Tatarinov, L.P. et al. (eds.) |title=Upper Paleozoic and Mesozoic Amphibians and Reptiles |year=1968 |publisher=Akademia Naul SSSR |location=Moscow |language=Russian |pages=97-141 |chapter=Hadrosaurs of Kazakhstan ] It may be synonymous with "Jaxartosaurus aralensis",cite book |last=Horner |first=John R. |authorlink=Jack Horner (paleontologist) |coauthors=Weishampel, David B.; and Forster, Catherine A |editor=Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.)|title=The Dinosauria |edition=2nd |year= 2004|publisher=University of California Press |location=Berkeley |isbn=0-520-24209-2 |pages=438-463 |chapter=Hadrosauridae ] or it could be its own genus, cite book |last=Norman |first=David B. |authorlink=David B. Norman |coauthors=Sues, Hans-Dieter |editor=Benton, Michael J.; Shishkin, Mikhail A.; Unwin, David M.; and Kurochkin, Evgenii N. |title=The Age of Dinosaurs in Russia and Mongolia |year=2000 |publisher=Cambridge University Press |location=Cambridge |isbn=0-521-55476-X |pages=462-479 |chapter=Ornithopods from Kazakhstan, Mongolia and Siberia ] which would require a new generic name.

References

External links

* [http://www.dinoruss.com/de_4/5a7af53.htm "Procheneosaurus" in The Dinosaur Encyclopaedia] at Dino Russ's Lair