Lawrence M. Witmer, professor of anatomy at OHIO's Heritage College of Osteopathic Medicine, and Ryan Ridgley, a research associate of 23 years in WitmerLab, specifically focused their research efforts and contributed information on Baryonyx, one of the species of spinosaurs highlighted in the study.

The most famous spinosaur is Spinosaurus itself, a 45-foot-long, sail-backed giant that was one of the stars of Jurassic Park III. Spinosaurs are an unusual group of 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 lived long before Spinosaurus and 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.