Piveteausaurus

File:Piveteausaurus divesensis.JPG

The partial braincase that became the type specimen of Piveteausaurus was first described in 1923 by French paleontologist Jean Piveteau in illustrations and photographs of the specimen (MNHN 1920-7). The braincase is comparable in size to that of a large Allosaurus,{{cite book|last=Holtz |first=Thomas R. Jr. |author-link=Thomas R. Holtz, Jr. |author2=Molnar, Ralph E. |author3= Currie, Philip J. |year=2004 |editor=Weishampel, David B. |editor2=Dodson, Peter |editor3=Osmólska, Halszka |title=The Dinosauria |url=https://archive.org/details/dinosauriandedit00weis |url-access=limited |edition=2nd |publisher=University of California Press |location=Berkeley |isbn=0-520-24209-2 |pages=[https://archive.org/details/dinosauriandedit00weis/page/n89 71]–110 }} and resembles that of another megalosauroid, Piatnitzkysaurus from Argentina.Rauhut, 2004. Braincase structure of the Middle Jurassic theropod dinosaur Piatnitzkysaurus. Canadian Journal of Earth Science. 41, 1109-1122. Piveteau grouped this partial skull with other specimens found earlier in that locality and described in 1808 by French naturalist Georges Cuvier.{{cite journal |last=Walker |first=Alick D. |author-link=Alick Walker |year=1964 |title=Triassic reptiles from the Elgin area: Ornithosuchus and the origin of carnosaurs |journal=Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences |volume=248 |issue=744 |pages=53–134 |doi=10.1098/rstb.1964.0009 |bibcode=1964RSPTB.248...53W|doi-access= }} 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 Marnes de Dives around 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.{{cite journal |last=Piveteau |first=Jean |author-link=Jean Piveteau |year=1923 |title=L'arrière-crâne d'un dinosaurien carnivore de l'Oxfordien de Dives [The braincase of a carnivorous dinosaur from the Oxfordian of Dives] |journal=Annales de Paléontologie |volume=12 |pages=115–123 |language=French }} Later these rocks were reevaluated as older (Upper Callovian, Middle Jurassic, ~164 million years old).{{cite book |last=Weishampel |first=David B. |author-link=David B. Weishampel |author2=Barrett, Paul M. |author3=Coria, Rodolfo A. |author4=Le Loeuff, Jean |author5=Xu Xing |author6=Zhao Xijin |author7=Sahni, Ashok |author8=Gomani, Elizabeth M.P. |author9=Noto, Christopher R. |chapter=Dinosaur distribution |editor=David B. Weishampel |editor2=Peter Dodson |editor3=Halszka Osmólska|title=The Dinosauria |url=https://archive.org/details/dinosauriandedit00weis |url-access=limited |edition=2nd |year=2004 |publisher=University of California Press |location=Berkeley |isbn=0-520-24209-2 |page=[https://archive.org/details/dinosauriandedit00weis/page/n558 540] }}

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 postcranial bones, conveniently associated with the skull by Walker, from the species.{{cite journal |author=Taquet |first=Philippe |author-link=Philippe Taquet |author2=Welles, Samuel P. |year=1977 |title=Redescription du crâne de dinosaure théropode de Dives (Normandie) [Redescription of a theropod dinosaur skull from Dives (Normandy)] |journal=Annales de Paléontologie (Vertébrés) |volume=63 |issue=2 |pages=191–206 |language=French}} In 1988 Gregory S. Paul synonymised Piveteausaurus with Proceratosaurus coining the new combination Proceratosaurus divesensis,{{cite book |last=Paul |first=Gregory S. |author-link=Gregory S. Paul |title=Predatory Dinosaurs of the World |year=1988 |publisher=Simon & Schuster |location=New York |isbn=0-671-61946-2 |pages=[https://archive.org/details/predatorydinosau00paul/page/304 304–305] |url-access=registration |url=https://archive.org/details/predatorydinosau00paul/page/304 }} but this assignment was rejected by other researchers.{{cite book |last=Molnar |first=Ralph E. |author-link=Ralph Molnar |author2=Kurzanov, Sergei M. |author3=Dong Zhiming |author3-link=Dong Zhiming |year=1990 |chapter=Carnosauria |editor=Weishampel David B. |editor-link=David Weishampel |editor2=Dodson, Peter |editor2-link=Peter Dodson |editor3=Osmólska, Halszka |title=The Dinosauria |edition=First |publisher=University of California Press |location=Berkeley |pages=169–209 |isbn=0-520-06727-4}}

While the braincase appears to be distinct, the limited remains mean Piveteausaurus has not been easy to classify. It has been compared to Ceratosaurus,{{cite journal |last=Bakker |first=Robert T. |author-link=Robert T. Bakker |author2=Kralis, Donald |author3=Siegwarth, James |author4= Filla, James |year=1992 |title=Edmarka rex, a new, gigantic theropod dinosaur from the middle Morrison Formation, Late Jurassic of the Como Bluff outcrop region |journal=Hunteria |volume=2 |issue=9 |pages=1–24}} Eustreptospondylus, and Proceratosaurus, and was interpreted as a species of the latter two genera at various times.

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 Tetanurae, 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.{{cite journal |last=Benson |first=R.B.J. |year=2010 |pages=882–935 |volume=158 |title=A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods |journal=Zoological Journal of the Linnean Society |issue=4 |doi= 10.1111/j.1096-3642.2009.00569.x |doi-access=free |url=https://zenodo.org/record/5438464 }}

The phylogenetic position of Piveteausaurus according to Carrano et al. (2012) is shown by this cladogram:M.T. Carrano, R.B.J. Benson, and S.D. Sampson, 2012, "The phylogeny of Tetanurae (Dinosauria: Theropoda)", Journal of Systematic Palaeontology 10(2): 211-300

{{clade| style=font-size:90%;line-height:90%;margin:1em auto;

|label1=Megalosauroidea

|1={{clade

|1=Piatnitzkysauridae 80px

|label2=Megalosauria

|2={{clade

|1=Streptospondylus

|2=Spinosauridae 70px

|label3=Megalosauridae

|3={{clade

|label1=Eustreptospondylinae

|1={{clade

|1=Eustreptospondylus 80px }}

|2={{clade

|label1=Megalosaurinae

|1={{clade

|1=Duriavenator 80px

|2={{clade

|1=Megalosaurus 80px

|2=Torvosaurus 80px }} }}

|label2=Afrovenatorinae

|2={{clade

|1=Afrovenator 80px

|2={{clade

|1=Dubreuillosaurus 80px

|2=Magnosaurus 80px }}

|3={{clade

|1=Leshansaurus

|2=Piveteausaurus }} }} }} }} }} }} }}

{{Reflist}}

• {{cite book|chapter=Piveteausaurus |last=Glut |first=Donald F. |author-link=Donald F. Glut |title=Dinosaurs: The Encyclopedia |url=https://archive.org/details/dinosaursencyclo05dfgl |url-access=limited |year=1997 |publisher=McFarland & Co |location=Jefferson, North Carolina |pages=[https://archive.org/details/dinosaursencyclo05dfgl/page/n711 706]–707 |isbn=0-89950-917-7}}

• [https://web.archive.org/web/20131219195023/http://archosaur.us/theropoddatabase/Megalosauroidea.htm#Piveteausaurusdivesensis Piveteausaurus] in the Theropod Database
• [https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=38593 Piveteausaurus] in the Paleobiology Database

{{Theropoda|T.}}

{{Taxonbar|from=Q134625}}

Category:Megalosauridae

Category:Dinosaur genera

Category:Oxfordian dinosaurs

Category:Taxa named by Philippe Taquet

Category:Taxa named by Samuel Paul Welles

Category:Fossil taxa described in 1977

Category:Dinosaurs of France