A curved slab of bone pulled from a remote fossil site called Jenguebi, deep in Niger’s central sand sea, revealed something paleontologists had not seen in more than a century: a new species of Spinosaurus, described this week in Science.
The dinosaur, named Spinosaurus mirabilis, lived about 95 million years ago in a wooded inland river system. It had the long, crocodile-like snout typical of its kind, but rising from its skull was something no known Spinosaurus had ever displayed: a tall, scimitar-shaped crest that likely extended even higher in life beneath a keratin sheath.
The search that led to Jenguebi began decades earlier, sparked by a line in a 1950s French monograph that mentioned a saber-shaped tooth in Niger, a reference that would later guide researchers back to the site.
“It was an expedition we lay in wait to embark on for many years. At the start, I told my team — girding them for the certain hardships and extreme conditions we would soon face — ‘This is our chance to write a chapter in the history of Africa’s dinosaur world, and sometimes that chance comes along only once in a lifetime’,” paleontologist Paul Sereno, who led the research team, told Discover.
Finding The Tall-Crested Spinosaurus mirabilis
Fragments of jaw and teeth first surfaced in 2019. But when the team returned in 2022, paleontologist Daniel Vidal uncovered the crest, a find that made it clear they weren’t looking at just another spinosaur.
Paleontologists Paul Sereno and Dan Vidal take notes on a massive hind limb of a new long-necked dinosaur.
(Image Courtesy of Matthew Irving; courtesy of Fossil La)
The crest rose high above the skull. Its dense bone and internal vascular channels suggest it supported a keratin sheath, similar to the casques of some modern birds. It wasn’t built for feeding or defense, but for display.
Upper and lower teeth interlocked in a tight mesh. Once prey slid between those conical crowns, there was little room to pull free, an arrangement more typical of fish than dinosaurs.
“It was immediate upon Dan’s plucking the recognizable crest from the sand […] We both knew what it meant. Three days later, after digitizing the bones we found and assembling them into the outlines of a skull in his laptop, we all crowded around with many gasping,” shared Sereno.
Read More: Unusually Small Dinosaur Fossil Helps Fill a 70-Million-Year Gap in Ornithopod Evolution
Inland Fossil Challenges Aquatic Spinosaurus Theory
Two Spinosaurus mirabilis sp. nov. spar over a carcass of the coelacanth.
(Image Courtesy of Dani Navarro)
Spinosaurus has been at the center of a debate over how it lived. Some researchers argue it hunted in shallow water; others believe it pursued prey underwater.
Most fossils of its better-known relative, Spinosaurus aegyptiacus, come from deposits near ancient coasts, a geography that supports either interpretation.
Jenguebi shifts that context. During the mid-Cretaceous, the site lay roughly 300 to 620 miles (500 to 1,000 kilometers) from the nearest marine margin. The bones were preserved in river sediments alongside long-necked dinosaurs and other terrestrial animals, pointing to a freshwater inland ecosystem.
The team approached the question quantitatively, comparing skull, neck, and hind-limb proportions across dozens of living and extinct predators. Spinosaurids clustered neither with land-hunting theropods nor with specialized aquatic divers. Instead, they aligned most closely with long-necked waders.
“The sediment that covered our new Spinosaurus, the long-necked dinosaurs buried nearby, and our plot of skull, neck and hind limb length among archosaurian predators, all pointed to Spinosaurus as a hellish heron-like beast, commanding the waterways in a wooded inland setting and feasting on the giant fish of the day,” Sereno explained to Discover.
What This New Spinosaurus Reveals About Evolution
Mirabilis means “astonishing.” The crest earns the name. But the greater revelation lies in where the animal was found. This fossil situates Spinosaurus within the rise and fall of a lineage that once dominated river systems along the margins of the ancient Tethys Sea, reached sizes rivaling the largest land predators, and vanished near the end of the Cenomanian.
For a dinosaur long shaped by competing interpretations, Jenguebi provides clarity.
Read More: 84-Million-Year-Old Horned-Dinosaur Fossils Rewrite Europe’s Prehistoric Record
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
