Saurosuchus galilei, a large loricatan pseudosuchian archosaur that lived in South America 230 million years ago (Late Triassic epoch), was thought to be an apex predator due to its size and diet, standing at between 5-8 m (16-26 feet) in length and weighing over 250 kg
However, the new analysis of Saurosuchus galilei’s skull and comparisons with the later well-known dinosaur Allosaurus found that despite their similar skull strengths, Saurosuchus galilei had a much weaker bite than the dinosaurs that followed it. Saurosuchus galilei would have had a bite with the force of 1015-1885 N, equivalent to modern crocodiles called gharials (for comparison, Allosaurus had a bite force of 3,572 N; saltwater crocodiles have a bite force of 16,000 N; Tyrannosaurus rex: 17,000-35,000 N).
Skull and life reconstruction of Saurosuchus galilei. Image credit: Jordan Bestwick, University of Birmingham.
“We found that Saurosuchus galilei actually had an incredibly weak bite for its size and thus predated animals in very different ways compared to later evolving dinosaurs,” said University of Birmingham vertebrate paleobiologist Dr. Jordan Bestwick.
“In fact, despite being one of the bigger lizards and an apex predator, Saurosuchus galilei had a bite that was on a par with the relatively measly bite of the gharial, and much less powerful than more fearsome crocs and alligators around today.”
“You would still have liked to leave Saurosuchus galilei well alone, but they likely fed only on the soft fleshy bits of their kills as their bite wouldn’t have enabled them to crunch up bones.”
Despite their relative size, Saurosuchus galilei would have been a careful diner that used their back teeth to remove the flesh from their kills.
In contrast to later dinosaurs, the feeding behavior of Saurosuchus galilei is likely due to a weak bite and a more rectangular skull shape.
Also these earlier reptiles had thinner bones in their noses compared to the later Allosaurus.
“Saurosuchus galilei would certainly have been a fearsome reptile until it sat down to eat its prey, and we can see how evolutionary details in the skulls of these massive apex predators necessitated significant differences in eating behavior,” said University of Birmingham paleobiologist Dr. Stephan Lautenschlager.
“While dinosaurs that followed in the Jurassic period would have eaten the vast majority of their kills, Saurosuchus galilei may have left more complete carcasses, which would have provided a secondary meal for carrion-feeding animals too.”
“It is truly amazing how similar the skulls of top predators in the Triassic period (the time before the domination of the dinosaurs) look compared to the well-known carnivorous dinosaurs such as Tyrannosaurus rex,” said University of Birmingham paleontologist Molly Fawcett.
“However, unexpectedly we found that the bite power of these Triassic predators were far weaker compared to the post-Triassic dinosaurs.”