200 million years ago Saltriovenator zanellai was the largest carnivorous dinosaur

Saltriovenator zanellai available bones (Image G. Bindellini / C. Dal Sasso / M. Zilioli / M. Auditore)
Saltriovenator zanellai available bones (Image G. Bindellini / C. Dal Sasso / M. Zilioli / M. Auditore)

An article published in the journal “PeerJ” describes the study of a carnivorous dinosaur of which a partial skeleton was discovered in 1996 near Saltrio, in the Varese province, about 80 kilometer North-East of Milan, Italy. Named Saltriovenator zanellai, it was classified as a part of the group of ceratosaurs, medium-large carnivorous dinosaurs, by Cristiano Dal Sasso, Simone Maganuco and Andrea Cau. It lived almost 200 million years ago and this makes it the oldest ceratosaurus discovered so far and with an estimated length of about 7.5 meters (about 25 feet) and probably at least one ton of weight it’s the largest theropod dinosaur of the time. Its characteristics offer information on birds’ three-fingered hands.

Various bones of what was later named Saltriovenator zanellai were discovered in 1996 by Angelo Zanella, an amateur fossil hunter who collaborates with the Museum of Natural History in Milan. Many bones show the signs of marine animals that had attached themselves to them or had eaten some parts of them and this suggests that, after the animal’s death, its corpse floated in a sea basin and then sank.

Probably at that time that area was occupied by a shallow sea with surrounding lands. Saltriovenator zanellai was likely a top predator in that ecosystem’s food chain and this suggests that the area was quite large to support the presence of herbivorous dinosaurs and a predator that had already reached that size. Actually, the paleohistological study of the uncovered specimen suggests that it was a subadult that hadn’t yet completed its growth, so its size is even more extraordinary.

Over time many bones of this specimen got scattered here and there and were probably destroyed so only a small part was found, enough to provide a lot of information on this dinosaur. In fact, it shows a set of characteristics that are partly primitive and partly advanced for the Lower Jurassic period in which it lived. Dilophosaurs and ceratosaurs were animals that had four-fingered hands while other groups that lived later such as allosaurs had three-fingered hands. Saltriovenator zanellai had three-fingered hands and represents an important step in the evolution of the anatomical structure that in theropod dinosaurs are the precursor of bird wings.

In the Lower Jurassic dinosaurs were beginning to become a dominant group after the extinction of predators belonging to other groups that occurred at the end of the Triassic period. This makes the discovery of Saltriovenator zanellai really interesting also to better understand the evolution of carnivorous dinosaurs. It took years to extract the bones from the hard rock in which they were found and clean them up but finally it was possible to study them thoroughly. There’s always hope to find other fossils from that period in the same area to better understand the ecosystem in which that predator lived.

Saltriovenator zanellai reconstruction (Image Davide Bonadonna)
Saltriovenator zanellai reconstruction (Image Davide Bonadonna)

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