A mighty, prehistoric meat-eater has been discovered in the Italian Alps. Paleontologists were confused about finding this four-fingered dinosaur in a seemingly random place. The newly identified creature—named Saltriovenator zanellai—lived about 200 million years ago and it’s the first Jurassic dinosaur discovered in Italy. It has also been named the oldest-known ceratosaurian, as well as the largest predatory dinosaur known from the early Jurassic period. Early Jurassic predatory dinosaurs, or at least those discovered so far, are very rare and often pretty small. The most important part of the Saltriovenator zanellai, however, is not its size or weight but its hands. Its hands could hold the answers to a variety of questions about where the common bird’s wing originated.
Not Quite The Oldest Dinosaur
The fossil found in the Italian Alps was at first believed to be the oldest known dinosaur fossil. However, an older one was discovered to have existed around 240 million years ago which is earlier than scientists previously theorized. This particular fossil was named Nyasasaurus parringtoni and it is only known from an upper arm and some backbones that were discovered in Tanzania in the early 1930s. Based on the fossils that were found, scientists estimated that it was between 6.5 to 10 feet long, including its tail. This led scientists to believe that all of the earlier dinosaurs were this size at least until Saltriovenator zanellai was discovered.
There is not much known about the oldest fossil since there were no skull bones recovered so it is unclear what the entire animal looked like. It could have been a theropod or a ceratosaurian like the newly discovered Saltriovenator. The discovery of Nyasasaurus parringtoni in Tanzania also supports the belief that dinosaurs originated in the southern part of the supercontinent known as Pangaea. Leading to the question of how did the fossilized remains of Saltriovenator zanellai end up in the Italian Alps?
Journey To Fossilization
Saltriovenator zanellai had a long journey before it was fossilized according to researchers. They believe that the dinosaur’s body somehow ended up in the sea where it was nibbled on by marine creatures before it was eventually buried. About 30 million years ago, the Alps began to form between the European continent and the Adriatic continent which brought the fossil out of the ground. According to the lead researcher, Cristiano Dal Sasso, a curator of vertebrate paleontology at the Milan Natural History Museum, finding this fossil was a miracle. “It’s a miracle that it survived such a long chain of events: drifting away to the sea, then floating, sinking, being scavenged by marine animals, reworked by sea bottom currents, buried, uplifted within a mountain chain, and eventually blow up by human explosives.”
The fossil was discovered in 1996 by an amateur fossil hunter, Angelo Zanella, in a marble quarry less than 50 miles northeast of Milan near Saltrio. Dal Sasso and his team took a look at the site, dug up more bones, and discovered that there were at least 30 bore marks on the bones from a variety of ancient marine invertebrates. A single tooth and a jaw fragment from bony fish were found with Saltriovenator which hinted to this dinosaur’s watery resting place.
The Evolutionary Tree
While the size of the dinosaur and its path of fossilization are intriguing, the biggest discovery about the Saltriovenator zanellai was told by its fingers. Dal Sasso and his team began piecing the dinosaur back together again and although many of the Saltriovenator zanellai bones were fragmented, there were plenty of signs to indicated that this beast had four fingers. The oldest-known dinosaurs had five fingers but all known ceratosaurs including Ceratosaurus and Eoabelisaururs, had four fingers. Many paleontologists, like Matthew Lamanna who is an assistant curator at Carnegie Museum of Natural History in Pittsburgh, believe that “somewhere on the evolutionary line to ceratosaurs, the fifth digit was lost, resulting in the four-fingered hand of ceratosaurs.”
The next branch on the evolutionary tree is the Theropods, a mostly carnivorous and two-legged dinosaur. Theropods evolved further from the ceratosaurs by losing their fourth finger, leading to the three-fingered hands such as those seen on the well-known Tyrannosaurus rex. Eventually, the three fingers turned into the bird wing we see today. This evolution from dinosaurs to birds has been debated for many years but this new discovery may finally bring that debate to an end.
A Missing Piece
Lamanna has also noted that there has been a debate on which finger the theropods actually lost when they evolved from ceratosaurs. Thankfully “Saltriovenator zanellai helps show that the three-fingered hand of these theropods was produced through the loss of the fourth finger rather than the first (thumb).” Scientists found an interesting and surprising fact about this dinosaur as they studied it further. The paleontologists who uncovered the Saltriovenator zanellai noticed before studying it that this dinosaur was very large, about 26 feet long but it was only a young adult. This means that the dinosaur they found wasn’t done growing yet. It hadn’t reached its full size when it died yet it was already one of the largest discovered.
This dinosaur could be the missing piece for a long line of unanswered questions. One question being: how did bird wings evolve? The long debate about birds evolving from dinosaurs may finally come to an end. After all, birds are considered as the lone surviving dinosaur lineage. More specifically, the last theropod dinosaurs around. Some researchers believe that a bird’s wings were the result of the first, second, and third digits of the theropod hand becoming fused.
Saltriovenator zanellai provides evidence that modern bird wings actually evolved from the first, second, and third digits of a distant ancestor. This may seem like a pointless debate, but it could provide us with a better understanding of how certain traits emerge in a species. With further research, scientists may be able to find connections between the different species of dinosaurs and the creatures that walk the Earth today.
