A semi-aquatic dinosaur that roamed southern England 125 million years ago inherited the brain’s ability to catch fish from its ancestors, a new study suggests.
Scientists at the Universities of Southampton and Ohio University have reconstructed the brains and inner ears of two species of Spinosaurus, which they say could help reveal how these large carnivorous dinosaurs interacted with their environment.
Spinosaurus adapted long, crocodile-like jaws and conical teeth to stalk prey, usually large fish, along river banks.
This way of life is a major change from that of other theropods such as Allosaurus and Tyrannosaurus rex
Researchers scan braincase of Baryonyx fossil Surrey and ceratosuchops from the Isle of Wight during the study.
The goal was to better understand the evolution of the Spinosaurus brain and senses — the results were published in the Journal of Anatomy.
Southampton PhD student Chris Barker, who led the research, said: “Despite their unusual ecological environment, the brains and senses of these early spinosaurs appear to have much in common with other large theropods – there is no evidence suggests that their semi-aquatic lifestyle is reflected in the way their brains are organized.”
One explanation for this evidence, he explained, is that the theropod ancestors of Spinosaurus already had the brain and sensory adaptations for part-time fishing.
He thinks this means that Spinosaurus only needed to evolve their unusual snout and teeth to be specifically adapted to a semi-aquatic life.
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Contributing author Dr Darren Naish said: “Since the skulls of all spinosaurs were so specialized for fishing, it was surprising to see such an ‘unspecialized’ brain.
“But the results are still important. It’s exciting to learn so much about sensory abilities — hearing, smell, balance, and more — from British dinosaurs.”
“Using cutting-edge technology, we have essentially obtained all possible brain-related information from these fossils.”
A University of Southampton spokesman said: “The skulls of both specimens were well preserved and the team digitally reconstructed the long-decayed inner soft tissues.
“The researchers found that the olfactory bulb, which processes odors, is not particularly well developed, and the ear may be sensitive to low-frequency sounds.
“The parts of the brain responsible for keeping the head steady and keeping an eye on prey were probably less developed than in later, more specialized Spinosaurus.”