125 Million-Year-Old Spinosaur Brains Revealed Through CT Scanning

Ceratosuchops Spinosaurid Artist's Impression

Artist’s impression of Ceratosuchops and the orientation of the endocast in the skull. Spinosaurs are a group of carnivorous theropod dinosaurs that lived during the Cretaceous period. They are characterized by their elongated, crocodile-like snouts, and the large, sail-like structures on their backs, which may have been used for display or regulating body temperature. Spinosaurs were among the largest predators of their time, with some species reaching lengths of up to 15 meters. Credit: Anthony Hutchings

A team of scientists hailing from the University of Southampton and Ohio University has successfully reconstructed the inner ears and brains of two spinosaurs from Britain, which has shed light on the ways in which these formidable carnivorous creatures interacted with their surroundings.

Spinosaurs are an unusual group of predatory theropod dinosaurs, equipped with long, crocodile-like jaws and conical teeth. These adaptations helped them live a somewhat-aquatic lifestyle that involved stalking riverbanks in quest of prey, among which were large fish. This way of life was very different from that of more familiar theropods, like Allosaurus and Tyrannosaurus.

To better understand the evolution of spinosaur brains and senses, the team scanned fossils of Baryonyx from Surrey and Ceratosuchops from the Isle of Wight. These two are the oldest spinosaurs for which braincase material is known. The huge creatures would have been roaming the planet about 125 million years ago. The braincases of both specimens are well preserved, and the team digitally reconstructed the internal soft tissues that had long rotted away.

The researchers found the olfactory bulbs, which process smells, weren’t particularly developed, and the ear was probably attuned to low-frequency sounds. Those parts of the brain involved in keeping the head stable and the gaze fixed on prey were possibly less developed than they were in later, more specialized spinosaurs.

Findings are due to be published in the Journal of Anatomy.

Baryonyx Endocast and Braincase

Three-dimensional reconstruction of the brain cavity and associated nerves and blood vessels within the braincase of the iconic british spinosaurid Baryonyx walkeri. Credit: WitmerLab/Chris_Barker

“Despite their unusual ecology, it seems the brains and senses of these early spinosaurs retained many aspects in common with other large-bodied theropods – there is no evidence that their semi-aquatic lifestyles are reflected in the way their brains are organized,” said University of Southampton PhD student Chris Barker, who led the study.

One interpretation of this evidence is that the theropod ancestors of spinosaurs already possessed brains and sensory adaptations suited for part-time fish catching, and that ‘all’ spinosaurs needed to do to become specialized for a semi-aquatic existence was evolve an unusual snout and teeth.

“Because the skulls of all spinosaurs are so specialized for fish-catching, it’s surprising to see such ‘non-specialized’ brains,” said contributing author Dr. Darren Naish. “But the results are still significant. It’s exciting to get so much information on sensory abilities – on hearing, sense of smell, balance and so on – from British dinosaurs. Using cutting-edged technology, we basically obtained all the brain-related information we possibly could from these fossils,” Dr. Naish said.

Over the last few years, the EvoPalaeo Lab at the University of Southampton has conducted substantial research on new spinosaurs from the Isle of Wight. Ceratosuchops itself was only announced by the team in 2021, and its discovery was followed up by the publication of another new spinosaur – the gigantic White Rock spinosaur – in 2022. The braincase of Ceratosuchops was scanned at the μ-Vis X-ray Imaging Centre at the University of Southampton, home to some of the most powerful CT scanners in the country, and a model of its brain will be on display alongside its bones at Dinosaur Isle Museum in Sandown, on the Isle of Wight.

“This new research is just the latest in what amounts to a revolution in paleontology due to advances in CT-based imaging of fossils,” said co-author Lawrence M. Witmer, professor of anatomy at the Ohio University Heritage College of Osteopathic Medicine, who has been CT scanning dinosaurs—including Baryonyx—for over 25 years. “We’re now in a position to be able to assess the cognitive and sensory capabilities of extinct animals and explore how the brain evolved in behaviourally extreme dinosaurs like spinosaurs.”

Ceratosuchops Endocast

Three-dimensional reconstruction of the brain cavity (purple), cranial nerves (yellow), inner ear (pink) and blood vessels (red and blue) of the British spinosaurid Ceratosuchops inferodios. This predator likely had an unexceptional sense of smell and could hear low frequency sounds. Credit: Chris Barker

“This new study highlights the significant role British fossils have in our constantly evolving, fast-moving understanding of dinosaurs, and shows how the UK – and the University of Southampton in particular – is at the forefront of spinosaur research,” said Dr. Neil Gostling who leads the University of Southampton’s EvoPalaeoLab. “Spinosaurs themselves are one of the most controversial of all dinosaur groups, and this study is a valuable addition to ongoing discussions of their biology and evolution.”

Reference: “Modified skulls but conservative brains? The palaeoneurology and endocranial anatomy of baryonychine dinosaurs (Theropoda: Spinosauridae)” by Chris Tijani Barker, Darren Naish, Jacob Trend, Lysanne Veerle Michels, Lawrence Witmer, Ryan Ridgley, Katy Rankin, Claire E. Clarkin, Philipp Schneider and Neil J. Gostling, 13 February 2023, Journal of Anatomy.
DOI: 10.1111/joa.13837

5 Comments on "125 Million-Year-Old Spinosaur Brains Revealed Through CT Scanning"

  1. Maniraptoran is a bird it’s not a dinosaur this is thecodont science

  2. I run into this story the won with website link.consevertive brain how can it be consevertive it is link to most advance dinosaur ever the gator .they identified vagus foramen because the gator and dinosaur are the same animal spinosauridae is a mesoeucrocodylia they have fuse vomer baryonyx neck ribs is reduce .baryonyx is the most derived theropod I know scientific language derived mean advance.so spinosauridae advance hearing started in baryonyx it was transition to the gator superior hearing they cliam it started when 6 bone fuse to the braincase but baryonyx has vagus foramen at the right place the nerve vagus canal lead to tympanic the eardrum this was found in 1973 the link to this story .baryonyx walkeri a fish eating dinosaur from the wealden of surrey .I am not finish with this report more reading

  3. Website change

  4. Baryonyx report says that it has fuse nasal is wrong it is a old report I thought they read it wrong the irritator fossil change the report the link is.irritator challengeri a spinosaurid academi edu.the surrey report allso say 7 foramen spinosaurus is like modern crocodilian at the same place has to be 7 is a match most animal have million of foramen in there skull only one foramen match modern crocodilian of baryonyx vagus foramen the spinosaurus link .a new information on the skull of the enigmatic academi edu. If 7 foramen of spinosaurus is a match spinosauridae is clearly a mesoeucrocodylia but we allready have enough evidence allready . The important of this most modern crocodilian lack fuse nasal only found in land crocodilian like one of dwarf caiman of today and baryonyx is simular to early gator type mesoeucrocodylia they share simular neck and death roll system but new fossil that is simular to baryonyx is more closer to modern crocodilian because they have a real gator tail not the extreme bipedal tail found in the first tetanuran .the 7 foramen of spinosaurus if they follow they mite get the answer

  5. The 6 bones fuse to the braincase they say only one of the bone lead to good hearing in protosuchus process bone is elongated like modern crocodilian this is reason they thought protosuchus is ancestor of modern crocodilian but they lack all feature of spinosauridae the real ancestor of modern crocodilian spinosauridae is a mesoeucrocodylia . Protosuchus modern crocodilian process bone are only thecodont with this feature that why there hearing is the best in thecodont but protosuchus bone is not fuse to the braincase .in modern crocodilian it is fuse to the braincase .so gator good hearing started out in baryonyx it was before elongated process bone .baryonyx brain is not consevertive it’s a high tech brain like modern crocodilian listen to the evidence

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