For more than a century, a puzzling fossil jawbone unearthed in South Wales has kept paleontologists guessing. First discovered in 1899 and long debated as to whether it belonged to a dinosaur, a crocodile relative, or something else entirely, the enigmatic specimen has finally been identified.
Researchers now confirm it represents one of the earliest known giant carnivorous dinosaurs — and they’ve given it a new name: “Newtonsaurus cambrensis.”
The finding, published in Proceedings of the Geologists’ Association, ends decades of scientific debate while rewriting the evolutionary timeline of predatory dinosaurs.
With its confirmation as a theropod, Newtonsaurus joins the ranks of iconic carnivores like Dilophosaurus and Coelophysis. However, it predates many of the dinosaurs, marking it as an evolutionary trailblazer at the dawn of the dinosaur age.
“A large jaw of a predatory archosaur from the latest Triassic of South Wales, named Zanclodon cambrensis, has long intrigued vertebrate palaeontologists,” the researchers write. “Could it be the oldest large theropod dinosaur? Here we reanalyse the specimen based on a new 3D digital reconstruction. We confirm first that it is indeed [the] latest Triassic in age, most likely extracted from sandstones of the Cotham Member of the Lilstock Formation.”
The fossil, a natural mold of a jawbone measuring approximately 11 inches (28 cm) in length, was first described in 1899 by Edwin Tully Newton, a paleontologist with the British Geological Survey. It had been unearthed at Stormy Down, a rocky limestone plateau near the town of Bridgend in South Wales, an area known for its Triassic-age deposits.
At the time, Newton suggested it resembled Megalosaurus, the first dinosaur ever scientifically named. However, without more complete bones for comparison, the fossil’s identity remained an open question.
Over the decades, experts shuffled the specimen between classifications, at times calling it a member of Zanclodon, a dubious genus of carnivorous reptiles, or hinting it could belong to crocodile-line archosaurs. Each revision left the fossil in a state of taxonomic limbo, with no consensus on whether it was truly a dinosaur.
The longstanding uncertainty about the fossil’s identity was resolved by a team of researchers from the University of Bristol, University College London, and the National Museum of Wales. Their use of cutting-edge 3D photogrammetry allowed for a detailed digital reconstruction of the fossil, enabling a comprehensive comparison of its anatomy with other known Triassic predators across Europe and North America.
The results of the reanalysis revealed that the fossil was not a misidentified crocodile cousin or a fragment of an already known genus. Instead, it represented a unique and distinct theropod dinosaur, large for its time, and deserving of its own genus.
In naming the new genus Newtonsaurus, the team honored Edwin Tully Newton, the scientist who first puzzled over the fossil 125 years ago. The species epithet cambrensis refers to Wales, where the specimen was found near the town of Bridgend at a site known as Stormy Down.
While the name “Newtonsaurus” had circulated informally in paleontological circles since the 1990s, this marks the first time it has been formally recognized in a peer-reviewed scientific paper.
“It was named Zanclodon cambrensis by Edwin Tully Newton in 1899, but we knew the name Zanclodon had been abandoned as referring to a broad variety of early reptiles,” lead author and University of Bristol paleontology student Owain Evans said in a press release. “Therefore, we name it after Newton, calling it Newtonsaurus. It is different from all other dinosaurs from around that time, and requires a distinctive name.”
What makes Newtonsaurus remarkable isn’t just its long history of misclassification but its age and size. The jaw dates back to the latest Triassic period, roughly 202 million years ago. This was an era when most theropods were small and lightly built.
Compared to other Triassic carnivores, Newtonsaurus was massive. The preserved portion of its lower jaw measured approximately 11 inches (28 cm) in length. Still, researchers estimate the complete mandible would have stretched roughly 23 inches (60 cm), belonging to a dinosaur that likely reached 16 to 23 feet (5-7 meters) in length.
The Newtonsaurus jaw shows traits linking it to coelophysoids like Liliensternus and Dracoraptor, but it was considerably larger. Its closest match appears to be Dilophosaurus, a predator from the Early Jurassic period.
The Dilophosaurus gained pop-culture fame in the Jurassic Park franchise, where it was memorably depicted with a dramatic neck frill and the ability to spit venom. In reality, there is no evidence in the fossil record to suggest Dilophosaurus had either of these features. Instead, it was a sleek, formidable predator, and the similarities between it and Newtonsaurus suggest the Welsh fossil represents a more advanced neotheropod than most of its Triassic contemporaries.
This makes Newtonsaurus one of the earliest known examples of a large-bodied theropod, pushing back the timeline for when giant predatory dinosaurs first emerged.
Until now, paleontologists believed truly large theropods didn’t appear until the Middle Jurassic, tens of millions of years later. This discovery, however, rewrites part of the dinosaur origin story, significantly shifting our understanding of when giant predatory dinosaurs first emerged.
The Newtonsaurus fossil used in this recent study isn’t made of bone but instead is a natural rock mold. The original bone decomposed long ago, leaving behind an impression in the surrounding sandstone. While these complicated efforts to identify it for more than a century, modern imaging finally unlocked the details hidden in the mold.
The team scanned the fossil with an industrial 3D scanner and reconstructed the jaw digitally in Blender software, revealing subtle anatomical features like grooves, foramina, and tooth sockets that had eluded earlier researchers.
The Stormy Down site, where the fossil was discovered, is part of the Lilstock Formation, a coastal sandstone deposited in a marginal marine environment. This setting suggests that the dinosaur’s remains were washed into shallow waters and entombed in sediment, explaining why the fossil survived as a mold rather than being preserved as a bone.
Alongside Newtonsaurus, South Wales has yielded other Triassic vertebrates, including small dinosaurs, early crocodylomorphs, and primitive reptiles. Together, they paint a picture of a transitional ecosystem where dinosaurs were beginning to rise as dominant land predators.
The confirmation of Newtonsaurus fills an essential gap in the fossil record. It shows that large theropods were present earlier than previously thought, reshaping our understanding of dinosaur evolution during the volatile period before the end-Triassic mass extinction.
This recent study also demonstrates how modern technology can breathe new life into old fossils. A specimen dismissed or debated for decades has now been reimagined as a landmark discovery.
Still, while Newtonsaurus finally resolves a 125-year-old mystery, it also opens the door to new questions. Was this predator an isolated giant roaming Late Triassic Wales, or part of a broader population of large theropods across Europe? Did it represent an evolutionary dead-end, snuffed out in the Triassic-Jurassic extinction event, or was it an early branch on the family tree that gave rise to the Jurassic’s most famous carnivores?
Scientists believe the answers may lie buried in the Triassic beds of South Wales, where more fossils could help complete the picture.
“These historical specimens are vitally important in paleontology and often yield new and exciting results – even if they have been sitting in collections for years. The Victorians were fascinated by the fossil record and prospected all across the UK for fossils,” co-author and curator at the National Museum of Wales, Cindy Howells, said. “On top of this, the re-description of Newtonsaurus cambrensis once again highlights the significance of Wales in paleontological research.”
“These Triassic beds are rare worldwide, and yet there are several across Wales,” Howells added.
“There might very well be another dinosaur waiting to be discovered.”
Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan. Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com