Piveteausaurus
Encyclopedia
Piveteausaurus is a genus
of theropod dinosaur
known from a partial skull
discovered in the Middle Jurassic
Marnes de Dives
formation of Calvados
, in northern France
.
Jean Piveteau
in illustrations and photographs of the specimen (MNHN
1920-7). The braincase is comparable in size to that of a large Allosaurus
, and resembles that of another megalosauroid, Piatnitzkysaurus
from Argentina
. Piveteau grouped this partial skull with other specimens found earlier in that locality and described in 1808 by French naturalist Georges Cuvier
. In 1861 English paleontologist Richard Owen
assigned the fragments to the species Streptospondylus
cuvieri, and Piveteau included the skull he found in the same species.
MNHN 1920-7 was found by local collector Dutacq in rocks thought to be Oxfordian
(Upper Jurassic), of the Vaches Noires cliffs near Dives
in Normandy
, France, and was after being reported by amateur geologist Cazenave in 1920 acquired by Professor Marcellin Boule
for the Muséum national d'histoire naturelle
. Later these rocks were reevaluated as older (Upper Callovian
, Middle Jurassic, ~161 million years old).
MNHN 1920-7 was reevaluated in 1964 by Alick Walker
as part of his work on Ornithosuchus
and the evolution of the Carnosauria
. He assigned MNHN 1920-7 to Eustreptospondylus
as the holotype
, or type specimen, of the new species E. divesensis. The other bone fragments described by Cuvier and attributed to S. cuvieri by Owen were also transferred, as a "matter of convenience," but without conviction on the part of Walker, to the new species, E. divesensis. It was given its own genus in 1977 by Philippe Taquet
and Samuel Welles
: Piveteausaurus, named after Piveteau. Taquet and Welles removed the postcrania
l bones, conveniently associated with the skull by Walker, from the species. Later the braincase would be regarded by Gregory S. Paul
as a species of Proceratosaurus
(P. divesensis), but this assignment was rejected by other researchers.
While the braincase appears to be distinct, the limited remains mean Piveteausaurus has not been easy to classify. It has been compared to Ceratosaurus
, Eustreptospondylus, and Proceratosaurus, and was interpreted as a species of the latter two genera at various times.
, though they did not include it in a phylogenetic analysis. The first such analysis was performed by Benson in 2010. He found that while its exact placement was unresolved, it always grouped with a member of the clade Megalosauridae, and so most likely belonged to that family.
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 theropod 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...
known from a partial skull
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
discovered in the Middle Jurassic
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....
Marnes de Dives
Marnes de Dives
The Marnes de Dives is a geological formation in Europe. It dates back to the Middle Jurassic.-Vertebrate fauna:...
formation of Calvados
Calvados
The French department of Calvados is part of the region of Basse-Normandie in Normandy. It takes its name from a cluster of rocks off the English Channel coast...
, in northern France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
.
History and description
The partial braincase that became the type specimen of Piveteausaurus was first described in 1923 by French paleontologistPaleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
Jean Piveteau
Jean Piveteau
Jean Piveteau was a distinguished French vertebrate paleontologist. He was elected to the French Academy of Sciences in 1956 and served as the institute's president in 1973.- External links :** at Google Books...
in illustrations and photographs of the specimen (MNHN
Muséum national d'histoire naturelle
The Muséum national d'Histoire naturelle is the National Museum of Natural History in Paris, France.- History :The museum was formally founded on 10 June 1793, during the French Revolution...
1920-7). The braincase is comparable in size to that of a large Allosaurus
Allosaurus
Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...
, and resembles that of another megalosauroid, Piatnitzkysaurus
Piatnitzkysaurus
Piatnitzkysaurus is a genus of theropod dinosaur. It is known from the Canadon Asfalto Formation, Middle Jurassic of what is now Argentina. Once thought to be a basal carnosaur, it may instead be a megalosauroid...
from Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. Piveteau grouped this partial skull with other specimens found earlier in that locality and described in 1808 by French naturalist Georges Cuvier
Georges Cuvier
Georges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist...
. In 1861 English paleontologist Richard Owen
Richard Owen
Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
assigned the fragments to the species Streptospondylus
Streptospondylus
Streptospondylus is a genus of tetanuran theropod dinosaur known from the Middle Jurassic period of France, 161 million years ago. It was a medium-sized predator.-Discovery and naming:...
cuvieri, and Piveteau included the skull he found in the same species.
MNHN 1920-7 was found by local collector Dutacq in rocks thought to be Oxfordian
Oxfordian stage
The Oxfordian is, in the ICS' geologic timescale, the earliest age of the Late Jurassic epoch, or the lowest stage of the Upper Jurassic series. It spans the time between 161.2 ± 4 Ma and 155.7 ± 4 Ma...
(Upper Jurassic), of the Vaches Noires cliffs near Dives
Dives-sur-Mer
-Transport:Dives-sur-Mer is on the line from Deauville to Dives-sur-Mer. The station is open, train services operate year round at weekends as well as on week days during the summer season. Dives is also on line #20 of the Calvados bus company Bus Verts du Calvados....
in Normandy
Normandy
Normandy is a geographical region corresponding to the former Duchy of Normandy. It is in France.The continental territory covers 30,627 km² and forms the preponderant part of Normandy and roughly 5% of the territory of France. It is divided for administrative purposes into two régions:...
, France, and was after being reported by amateur geologist Cazenave in 1920 acquired by Professor Marcellin Boule
Marcellin Boule
Marcellin Boule was a French palaeontologist.He studied and published the first analysis of a complete Homo neanderthalensis. The fossil discovered in La Chapelle-aux-Saints was an old man, and Boule characterized it as brutish, bent kneed and not a fully erect biped...
for the Muséum national d'histoire naturelle
Muséum national d'histoire naturelle
The Muséum national d'Histoire naturelle is the National Museum of Natural History in Paris, France.- History :The museum was formally founded on 10 June 1793, during the French Revolution...
. Later these rocks were reevaluated as older (Upper Callovian
Callovian
In the geologic timescale, the Callovian is an age or stage in the Middle Jurassic, lasting between 164.7 ± 4.0 Ma and 161.2 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian....
, Middle Jurassic, ~161 million years old).
MNHN 1920-7 was reevaluated in 1964 by Alick Walker
Alick Walker
Alick Donald Walker was a British palaeontologist, after whom the Alwalkeria genus of dinosaur is named....
as part of his work on Ornithosuchus
Ornithosuchus
Ornithosuchus is an extinct genus of crurotarsan from the Late Triassic Lossiemouth Sandstone of Scotland...
and the evolution of the Carnosauria
Carnosauria
Carnosauria is a group of large predatory dinosaurs that lived during the Jurassic and Cretaceous periods. While it originally contained a wide assortment of giant theropods that were not closely related, the group has since been defined to encompass only the allosaurs and their closest kin...
. He assigned MNHN 1920-7 to Eustreptospondylus
Eustreptospondylus
Eustreptospondylus is a genus of megalosaurid dinosaur, from the Callovian stage of the Middle Jurassic period in southern England, at a time when Europe was a series of scattered islands Eustreptospondylus ("well-curved vertebra", in reference to the arrangement of the spine in the original...
as the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
, or type specimen, of the new species E. divesensis. The other bone fragments described by Cuvier and attributed to S. cuvieri by Owen were also transferred, as a "matter of convenience," but without conviction on the part of Walker, to the new species, E. divesensis. It was given its own genus in 1977 by Philippe Taquet
Philippe Taquet
Philippe Taquet is a French paleontologist who specializes in dinosaur systematics of finds primarily in northern Africa.He is a member of the French Academy of Sciences since November 30, 2004...
and Samuel Welles
Samuel Paul Welles
Samuel Paul Welles was an American palaeontologist, who was Research Associate at the Museum of Palaeontology, University of California, Berkeley. He took part in excavations at the 'Placerias Quarry' in 1930 and the Shonisaurus discoveries of 1954 and later, in what is now the Berlin-Ichthyosaur...
: Piveteausaurus, named after Piveteau. Taquet and Welles removed the postcrania
Postcrania
Postcrania[p] in zoology and vertebrate paleontology refers to all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g...
l bones, conveniently associated with the skull by Walker, from the species. Later the braincase would be regarded by Gregory S. Paul
Gregory S. Paul
Gregory Scott Paul is a freelance researcher, author and illustrator who works in paleontology, and more recently has examined sociology and theology. He is best known for his work and research on theropod dinosaurs and his detailed illustrations, both live and skeletal...
as a species of Proceratosaurus
Proceratosaurus
Proceratosaurus is a genus of small-sized carnivorous theropod dinosaur from the Middle Jurassic of England. It was originally thought to be an ancestor of Ceratosaurus, due to the similar small crest on its snout...
(P. divesensis), but this assignment was rejected by other researchers.
While the braincase appears to be distinct, the limited remains mean Piveteausaurus has not been easy to classify. It has been compared to Ceratosaurus
Ceratosaurus
Ceratosaurus meaning "horned lizard", in reference to the horn on its nose , was a large predatory theropod dinosaur from the Late Jurassic Period , found in the Morrison Formation of North America, in Tanzania and Portugal...
, Eustreptospondylus, and Proceratosaurus, and was interpreted as a species of the latter two genera at various times.
Classification
Piveteausaurus was originally regarded as a megalosaurid as a "matter of convenience", as its describers did not want to name a new family for such fragmentary remains. Tom Holtz and colleagues (2004) considered it to be an indeterminate member of TetanuraeTetanurae
Tetanurae, or "stiff tails", is a clade that includes most theropod dinosaurs, as well as birds. Tetanurans first appear during the early or middle Jurassic Period.-Definition:...
, though they did not include it in a phylogenetic analysis. The first such analysis was performed by Benson in 2010. He found that while its exact placement was unresolved, it always grouped with a member of the clade Megalosauridae, and so most likely belonged to that family.
External links
- Piveteausaurus in the Theropod Database
- Piveteausaurus in the Paleobiology DatabasePaleobiology Database' is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.-History:The Paleobiology Database was founded in 2000. It has been funded by the National Science Foundation and the Australian Research Council...