In one of the most dramatic dinosaur discoveries in years, scientists working in a remote stretch of Niger’s Sahara Desert have uncovered fossils of a new species of Spinosaurus — a colossal predator that once stalked Africa’s rivers nearly 95 million years ago.
Named Spinosaurus mirabilis, meaning “astonishing spine lizard,” the dinosaur lived up to its title. Stretching roughly 40 feet long and weighing between five and seven tons, it cut an unforgettable figure across the Cretaceous landscape. With a towering, blade-shaped head crest resembling a curved scimitar and a sail-like structure rising from its back, the predator looked as formidable as it was specialized.
But it was not a land-bound hunter in the mold of Tyrannosaurus rex. Instead, researchers describe it as something far more unusual — a semiaquatic giant that waded into rivers to snare massive fish. Lead author Paul Sereno of the University of Chicago dubbed it a “hell heron,” evoking the image of a monstrous wading bird stalking prey in shallow waters.
The fossils, detailed Thursday in the journal Science, represent only the second known species of Spinosaurus. The first, Spinosaurus aegyptiacus, was identified in 1915 from Egyptian remains. While the two species shared long dorsal spines forming a sail and elongated crocodile-like snouts adapted for fishing, S. mirabilis stands apart in striking ways.
Its 20-inch-tall cranial crest is significantly larger and appears too fragile for combat, suggesting it was used for display. Researchers believe the structure — likely covered in keratin, similar to a bull’s horns — may have been brightly colored and used in attracting mates or warding off rivals. “It’s about love and life — attracting a mate, defending your hot feeding shallows,” Sereno said.
The dinosaur’s anatomy reinforces its role as a fish specialist. Its nostrils were positioned farther back on the skull, allowing it to submerge most of its snout while breathing. Its conical, non-serrated teeth interlocked tightly in a formation known as interdigitation, creating what co-author Daniel Vidal described as a “fish trap” ideal for gripping slippery prey like coelacanths.
The inland location of the fossils — hundreds of miles from the ancient coastline of the Tethys Sea — may settle a long-running debate about whether Spinosaurus was fully aquatic. Some scientists had proposed it was an open-water swimmer and diving predator.
But the discovery of S. mirabilis far from marine environments supports the idea that it was instead a shallow-water hunter. Sereno called the find “the coup de grâce” for the fully aquatic hypothesis.
Reaching the site at Jenguebi was no small feat. In 2022, the research team drove off-road from Agadez for nearly three days, navigating dunes and repeatedly getting stuck in the sand. The effort yielded parts of three skulls and additional bones, along with fossils from other species that once shared the environment.
