Procheneosaurus
Encyclopedia
Procheneosaurus 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
, but later work indicates Hypacrosaurus
was included as well. 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
. 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. 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, 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, 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. 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. It may be synonymous with Jaxartosaurus aralensis
, or it could be its own genus, which would require a new generic name.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of hadrosaur dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
, based on small skulls with low domes in front of the eyes. It is now believed that the remains referred to its various species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
were from juvenile
Juvenile (organism)
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles sometimes look very different from the adult form, particularly in terms of their colour...
individuals of multiple genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of crested hadrosaurs
Lambeosaurinae
Lambeosaurinae is a group of crested hadrosaurid dinosaurs.-Classification:Lambeosaurines have been split into Parasaurolophini and Corythosaurini . Corythosaurini and Parasaurolophini as terms entered the formal literature in Evans and Reisz's 2007 redescription of Lambeosaurus magnicristatus...
. Peter Dodson
Peter Dodson
Peter Dodson is an American paleontologist who has published many papers and written and collaborated on books about dinosaurs. An authority on Ceratopsians, he has also authored several papers and textbooks on hadrosaurs and sauropods, and is a co-editor of The Dinosauria, widely considered the...
's 1975 work first broke them down among Corythosaurus
Corythosaurus
Corythosaurus is a genus of duck-billed dinosaur from the Upper Cretaceous Period, about 77-76.5 million years ago. It lived in what is now North America...
and Lambeosaurus
Lambeosaurus
Lambeosaurus is a genus of hadrosaurid dinosaur that lived about 76 to 75 million years ago, in the Late Cretaceous Period of North America. This bipedal/quadrupedal, herbivorous dinosaur is known for its distinctive hollow cranial crest, which in the best-known species resembled a hatchet...
, but later work indicates Hypacrosaurus
Hypacrosaurus
Hypacrosaurus was a genus of duckbill dinosaur similar in appearance to Corythosaurus. Like Corythosaurus, it had a tall, hollow rounded crest, although not as large and straight...
was included as well. 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.
William Diller Matthew
William Diller Matthew FRS was a vertebrate paleontologist who worked primarily on mammal fossils....
in 1920 in a photo caption for a skeleton and skull from the late Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...
-age Upper Cretaceous Dinosaur Park Formation
Dinosaur Park Formation
The Dinosaur Park Formation is the uppermost member of the Judith River Group, a major geologic unit in southern Alberta. It was laid down over a period of time between about 76.5 and 75 million years ago. The formation is made up of deposits of a high-sinuosity fluvial system, and is capped...
of Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. 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
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the 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. 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
Trachodon
Trachodon is a dubious genus of hadrosaurid dinosaur based on teeth from the Campanian-age Upper Cretaceous Judith River Formation of Montana, U.S.A...
" altidens, and may also be a specimen of Lambeosaurus, although it is based on only a maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
, 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
Charles Mortram Sternberg
Charles M. Sternberg was an American-Canadian fossil collector and paleontologist, son of Charles Hazelius Sternberg.Late in his career, he collected and described Pachyrhinosaurus, Brachylophosaurus, Parksosaurus and Edmontonia...
, was slightly larger than the other species, 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. 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
Two Medicine Formation
The Two Medicine Formation is a geologic formation, or rock body, that was deposited between 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma , during Campanian time, and is located in northwestern Montana...
of Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
, USA, appears to belong to a young Hypacrosaurus stebingeri
Hypacrosaurus
Hypacrosaurus was a genus of duckbill dinosaur similar in appearance to Corythosaurus. Like Corythosaurus, it had a tall, hollow rounded crest, although not as large and straight...
.
P. convincens, from the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
of Kazakhstan
Kazakhstan
Kazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...
, is known from a nearly complete skeleton missing only the snout and end of the tail. It was named by A. K. Rozhdestvensky
Anatoly Konstantinovich Rozhdestvensky
Anatoly Konstantinovich Rozhdestvensky was a Russian paleontologist responsible for naming many dinosaurs, including Aralosaurus and Probactrosaurus....
in 1968. It may be synonymous with Jaxartosaurus aralensis
Jaxartosaurus
Jaxartosaurus is a genus of hadrosaurid dinosaur similar to Corythosaurus which lived during the Late Cretaceous. Its fossils were found in Kazakhstan and China. It had a large, helmet-like crest that it may have used for visual identification, or to vocalize with members of the same herd.The type...
, or it could be its own genus, which would require a new generic name.
External links
- Procheneosaurus in The Dinosaur Encyclopaedia at Dino Russ's Lair