Palaeontologists have uncovered a previously unknown species of Spinosaurus, providing the first clear evidence in over a century of this dinosaur’s diversity. The discovery, led by Paul Sereno of the University of Chicago, was made in Niger’s central Sahara and includes jaw fragments, teeth, and three scimitar-shaped crests from the skull.
The first crest was unearthed in 2019. A larger team returned in 2022 and found two more, confirming it belonged to a new species. Named Spinosaurus mirabilis, the animal is thought to have had brightly coloured crests up to 50 centimetres high, likely used to attract mates or signal health.
“This discovery was sudden and emotional for our team,” Sereno said. “Seeing the 3D models of the skull on a laptop powered by solar panels in the Sahara was unforgettable.”
Inland predator, not deep diver
The fossils were found at a site known as Jenguebi, hundreds of kilometres from the nearest coastline. This challenges long-held assumptions that spinosaurs were largely aquatic hunters. Fossils of related species have mostly been found in coastal regions, which, along with adaptations like long jaws and crocodile-like teeth, suggested some could hunt underwater.
Sereno describes S. mirabilis as a “hell heron,” a wader that could enter water up to two metres deep but spent most of its time hunting in shallower rivers and lakes. Its interlocking teeth were ideal for catching large, slippery fish.
“This inland species shows that spinosaurs were not fully aquatic,” Sereno said. “They were skilled waders, stalking fish rather than diving like modern crocodiles.”
The dinosaur lived about 95 million years ago during the Cenomanian age of the Late Cretaceous. Based on fossil evidence, it could grow between 10 and 14 metres long, nearly as large as the famous Spinosaurus aegyptiacus. Its large head crest and sail were likely used for visual displays, helping it defend territory or attract mates.
Sereno and his team have been exploring the Sahara for decades. Once a lush environment of forests and rivers, the desert is now barren. The team plans to display replicas of S. mirabilis’ skull and crest at the Chicago Children’s Museum on 1 March.
“Sharing the excitement of discovery with children is vital,” Sereno said. “It inspires the next generation of scientists who will explore and protect our planet.”
The findings, published today in Science, provide a new perspective on spinosaurs and settle debates over their lifestyle. Experts say the evidence strongly supports a wading, fish-hunting behaviour rather than deep diving.
David Hone from Queen Mary University of London said, “These dinosaurs were not super swimmers. They were more like herons, wading into water to catch prey.”
Mark Witton of the University of Portsmouth added, “The anatomy of the legs and body clearly shows they were built to walk and wade rather than swim in deep water.”
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