Piveteausaurus

A fragment of the cranium, which became the model of the Piveteausaurus , was first described in 1923 by the French paleontologist Jean Piveto with illustrations and photographs of the model MNHN 1920-7. The skull box is comparable in size to the skull box of a large allosaurus ^[3] and is similar to that of another representative of the Megalosauroidea superfamily - Piatnitzkysaurus from Argentina ^[4] . Piveto grouped the skull box with other samples found in the same area and described in 1808 by the French naturalist Georges Cuvier . In 1861, the English paleontologist Richard Owen assigned the fragments to the species Streptospondylus cuvieri, and Peveto included the skull box sample in the same form ^[5] .

Sample MNHN 1920-7 was discovered by a local resident, a certain Dyutak, in rock formations dating from the Oxfordian tier of the Upper Jurassic, near the town of Div-sur-Mer in Normandy . The find was reported by amateur geologist Cazenav in 1920; The sample was bought by Professor Marcellin Boule for the National Museum of Natural History . Later, the age of the rocks where the sample was found was reevaluated and dated by the Upper Callovian (approximately 164 million years ago) ^[6] .

In 1964, the sample was re-examined by Alik Walker as part of his work on birdwatching and the evolution of carnosaurs . He attributed the fossil to the genus Eustreptospondylus as a holotype for a new species, E. divesensis . Other bone fragments described by Cuvier and assigned to Owten by Streptospondylus cuvieri were also classified as Eustreptospondylus divesensis “for convenience”, but without firm assurance on the part of Walker ^[5] . In 1977, paleontologists Philippe Take and Samuel Wells gave this sample their own generic name, Piveteausaurus , named after Jean Piveto. Take and Wells ruled out the postcranial bones that Walker had associated with the skull ^[7] . Later, Gregory S. Paul considered the skull to belong to Proceratosaurus divesensis ^[8] , however, this appointment was rejected by other researchers ^{[3] [9]} .

If the skull is not connected to other bones, then the Piveteausaurus is extremely difficult to classify. It was compared with the ceratosaurus ^[10] , Eustreptospondylus ^{[5] [9]} and Proceratosaurus ^[8] and was interpreted as a species of the last two genera at different times.

Initially, Piveteausaurus was attributed to the Megalosauridae family, since the authors of the description did not want to create a new family from fragmentary residues. Tom Holtz and his colleagues (2004) considered him an indefinite member of the group of tetanures , although they did not include him in his phylogenetic analysis ^[3] . The first analysis involving the sample was performed in 2010 by R. Benson. He found that although the exact location in the phylogenetic tree could not be determined, Piveteausaurus always grouped with a representative of the megalosaurids family, and therefore almost certainly is a member of this group ^[11] .

In 2012, a group of paleontologists led by Matthew Carrano refined the systematics of Piveteausaurus and assigned it to the subfamily Afrovenatorinae of the Megalosauridae family ^[12] .

• Glut, Donald F. Piveteausaurus // Dinosaurs: The Encyclopedia. - Jefferson, NC: McFarland & Co, 1997. - P. 706-707. - ISBN 0-89950-917-7 .
• Buffetaut E., Cuny G., and Le Loeuff J. French Dinosaurs: The Best Record in Europe? (Eng.) // Modern Geology. - 1991. - Vol. 16, no. 1-2 . - P. 24-25.

• Piveteausaurus at Theropod Database.