6 days ago
Crushers to slashers: Dinosaur bite styles reveal evolution's many paths
A new study finds that meat-eating dinosaurs followed remarkable evolutionary paths regarding their skull design and feeding style.
In a new study published in Cell, researchers from the University of Bristol investigated the largest carnivore dinosaurs, the Theroposa family. The T. rex is the most iconic member of that group, and it is also famous for producing the largest bipedal carnivore in Earth's history.
'Carnivorous dinosaurs took very different paths as they evolved into giants in feeding biomechanics and possible behaviors,' said Andrew Rowe of the University of Bristol, UK.
The new study explores how the skulls of these bipedal meat-eating giants evolved and offers intriguing insights into a way of life that exists no longer.
These dinosaurs are big, but what does that mean about their skulls?
A new study out of the University of Bristol analyzed the bite strength of 18 species of carnivorous dinosaurs. Study authors Andrew Rowe and Emily Rayfield wanted to know how bipedalism influenced skull biomechanics and feeding techniques.
Experts already knew that although this group of dinosaurs reached similar sizes, predators evolved at different times and in disparate parts of the world. And their skulls reflected that. Study authors wanted to dive in and assess how these skulls compared.
What is the relationship between their body size and skull biomechanics?
A snapshot of how carnivores developed
Rowe and Rayfield used 3D technologies, including CT and surface scans, to analyze skull mechanics, quantify feeding performance, and measure bite strength across 18 species of theropod, according to a press release.
The Tyrannosaurus rex skull was optimized for quick, strong bites like a crocodile. However, its evolutionary path was different from that of other giant predatory species, such as spinosaurs and allosaurs, which walked on two legs. It had weaker bites and instead specialized in slashing and ripping flesh.
'Tyrannosaurs evolved skulls built for strength and crushing bites, while other lineages had comparatively weaker but more specialized skulls, suggesting diverse feeding strategies even at massive sizes. In other words, there wasn't one 'best' skull design for being a predatory giant; several designs functioned perfectly well,' says Andrew Rowe from the University of Bristol.
But the Tyrannosaurids, like the T. rex, experienced higher skull stress. 'But in some other giants, like Giganotosaurus, we calculated stress patterns suggesting a relatively lighter bite. It drove home how evolution can produce multiple 'solutions' to life as a large, carnivorous biped.'
Does size matter?
But size didn't necessarily matter in this case. Some smaller therapods experienced more stress than some of the larger species due to increased muscle volume and bite forces.
'The findings show that being a predatory biped didn't always equate to being a bone-crushing giant. Unlike T. rex, some dinosaurs, including the spinosaurs and allosaurs, became giants while maintaining weaker bites more suited for slashing at prey and stripping flesh,' concludes a press release.
'I tend to compare Allosaurus to a modern Komodo dragon in terms of feeding style,' says Rowe. 'Large tyrannosaur skulls were instead optimized like modern crocodiles with high bite forces that crushed prey. This biomechanical diversity suggests that dinosaur ecosystems supported a wider range of giant carnivore ecologies than we often assume, with less competition and more specialization.'
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