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| Spinosaurus mirabilis Image Credit: Scientific Frontline / AI generated |
Scientific Frontline: "At a Glance" Summary: Hell-Heron Dinosaur Discovery
- Main Discovery: Paleontologists unearthed Spinosaurus mirabilis, a previously unknown species of giant, fish-eating dinosaur characterized by a distinct scimitar-shaped head crest and interlocking teeth.
- Methodology: Researchers conducted field excavations in the central Sahara of Niger over two expeditions in 2019 and 2022, subsequently using CT scans and laboratory analysis to assemble a comprehensive 3D digital skull rendering.
- Key Data: The fossils were located approximately 620 miles inland from the nearest prehistoric marine shoreline and date back roughly 95 million years.
- Significance: The geographical placement of the remains overturns existing hypotheses that spinosaurids were fully aquatic coastal hunters, suggesting instead that they functioned as wading predators within shallow, inland river ecosystems.
- Future Application: The physical replicas and 3D models of the dinosaur will be utilized in educational exhibits at the Chicago Children's Museum and a new zero-energy museum in Niger to foster public engagement with paleontological heritage.
- Branch of Science: Paleontology and Evolutionary Biology
- Additional Detail: Analysis of the crest's interior vascular canals and surface texture indicates it was sheathed in keratin during the animal's life and likely displayed bright colors to act as a visual beacon.
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| Skull cast of the new scimitar-crested spinosaurid "Spinosaurus mirabilis." Photo Credit: Keith Ladzinski |
When the paleontologists first plucked a massive, scimitar-shaped bone from the desolate sands of the central Sahara in 2019, they didn't immediately recognize it for what it was.
It took a return expedition, two more crests and a 3D digital skull assembly powered by solar panels in the middle of the desert in Niger before the realization sank in—they’d unearthed the towering head crest of an entirely new species of dinosaur.
"This find was so sudden and amazing, it was really emotional for our team," said Paul Sereno, professor of organismal biology and anatomy at the University of Chicago, who led the 20-person group. "I'll forever cherish the moment in camp when we crowded around a laptop to look at the new species for the first time."
A new paper published in Science describes their journeys in 2019 and 2022 to find Spinosaurus mirabilis, the first new spinosaurid species discovered in more than a century.
A large, fish-eating predator, S. mirabilis adds important new fossil finds to the closing chapter of its genus’s evolution. Based on the crest’s surface texture and interior vascular canals, the experts believe it was sheathed in keratin and brightly colored in life, curving toward the sky as a blade-shaped beacon.
Another striking feature of the skull is its interlocking teeth, where those of the lower jaw protrude outward and between those of the uppers to make a deadly trap for slippery fish. This is a common adaptation among fish-eaters in the fossil record—including aquatic ichthyosaurs, semi-aquatic crocodiles and airborne pterosaurs. Among dinosaurs, it sets Spinosaurus and closest kin apart.
Before, spinosaurid bones and teeth had been found mainly in coastal deposits not far from the shoreline, leading some experts to hypothesize that these fish-eating theropods may have been fully aquatic, pursuing prey underwater.
However, the new fossil area in Niger documents animals that were living inland, some as far as about 620 miles from the nearest marine shoreline. Their proximity to intact partial skeletons of long-necked dinosaurs, all buried in river sediments, suggests they lived in a forested inland habitat dissected by rivers.
“I envision this dinosaur as a kind of ‘hell heron’ that had no problem wading on its sturdy legs into two meters of water but probably spent most of its time stalking shallower traps for the many large fish of the day,” Sereno said.
A remarkable expedition to Niger
The journey that culminated in this discovery started with a single sentence in a monograph from the 1950s, where a French geologist mentioned finding a single saber-shaped fossilized tooth resembling those of the giant predator Carcharodontosaurus found in Egypt’s Western Desert at the turn of the last century.
Deep in the deserts of Niger, a UChicago-led team unearthed "Spinosaurus mirabilis"—the first new species of its kind in more than a century. Led by paleontologist Paul Sereno, the expedition upends long-held assumptions about how these fish-eating giants lived.
“No one had been back to that tooth site in over 70 years,” Sereno mused. “It was an adventure and a half wandering into the sand seas to search for this locale and then find an even more remote fossil area with the new species. Now all of the young scholars who joined me are co-authors on the report gracing the cover of Science.”
The team ended up meeting a local Tuareg man who led them on his motorbike deep into the center of the Sahara, where he had seen huge fossil bones. After nearly a full day of travel with no shortage of doubts regarding the success of the effort, he led them to a fossil field. There, with little time to spare before returning to camp, the team found teeth and jaw bones of the new species of Spinosaurus.
Sereno has excavated more than 100 tons of fossil finds in the Sahara over the past 30 years—much of which have added to Niger’s rich legacy in paleontology and archaeology. He has also led an international award-winning effort to build the world’s first zero-energy museum, the Museum of the River, on an island in the center of Niger’s capital city of Niamey.
This facility will showcase the country’s world-class patrimony that documents Africa’s lost world of dinosaurs, now including an astonishing spinosaur species, as well as stone-age cultures that once lived in a green, humid Sahara.
“The local people we work with are my lifelong friends, now including the man who led us to Jenguebi and the astonishing spinosaur. They understand the importance of what we’re doing together—for science and for their country,” Sereno said.
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This upwardly sweeping crest of the new spinosaurid "Spinosaurus mirabilis" was discovered by Spanish paleontologist Dan Vidal, instantly revealing that it pertained to a never-before-seen species.
Photo Credit: Daniel Vidal
Bringing Spinosaurus mirabilis to the world
Back home in Chicago, Sereno’s team at his South Side Fossil Lab in Washington Park cleaned and then CT scanned the teeth and bones, assembling a digital skull rendering for the research report. Using that rendering, Sereno worked with paleoartist Dani Navarro in Madrid to create an action scene involving flesh reconstructions of the new species tussling over a coelacanth carcass. Navarro went farther, creating a detailed 3D physical model of S. mirabilis by adding flesh over a skeletal reconstruction.
Other paleoartists—Jonathan Metzger in Chicago and Davide la Torre in Italy—animated Navarro’s model, bringing to life the scene chosen for the cover of Science.
As part of these reconstruction efforts, the team also prepared a replica of the newly discovered skull and a touchable, colorful model of the scimitar crest.
On March 1, in the wake of the Science paper, both replicas will join Sereno’s previous Dinosaur Expedition exhibit at the Chicago Children’s Museum, where young learners will be among the first to see this latest dinosaur find.
“Letting kids feel the excitement of new discoveries—that’s key to ensuring the next generation of scientists who will discover many more things about our precious planet worth preserving,” Sereno said.
Title: Scimitar-crested Spinosaurus species from the Sahara caps stepwise spinosaurid radiation
Authors: Paul C. Sereno, Daniel Vidal , Nathan P. Myhrvold, Evan Johnson-Ransom, María Ciudad Real, Stephanie L. Baumgart, Noelia Sánchez Fontela, Todd L. Green, Evan T. Saitta, Boubé Adamou, Lauren L. Bop, Tyler M. Keillor, Erin C. Fitzgerald, Didier B. Dutheil, Robert A. S. Laroche, Alexandre V. Demers-Potvin, áLvaro Simarro, Francesc Gascó-Lluna, Ana Lázaro, Arturo Gamonal, Charles V. Beightol, Vincent Reneleau, Rachel Vautrin, Filippo Bertozzo, Alejandro Granados, Grace Kinney-Broderick, Jordan C. Mallon, Rafael M. Lindoso, and Jahandar Ramezani
Source/Credit: University of Chicago | Grace Niewijk
Reference Number: pal022026_01