Paleontologists at the University of Bristol have identified a new species of dinosaur from Triassic rock beds in South Wales, more than a century after the fossil was first unearthed near Penarth.
The fossilized jawbone was originally reported in 1899 and has been displayed at the National Museum of Wales for decades. Researchers could not confirm whether it even belonged to a dinosaur. Now, using digital scanning and 3D reconstruction, scientists say the specimen represents a previously unrecognized predatory species.
The study, published in the Proceedings of the Geologists' Association, is titled "Re-assessment of a Large Theropod Dinosaur Dentary from the Rhaetian of South Wales."
The fossil consists only of natural molds in the rock; all of the original bone material is gone. Using photogrammetry and photo scanning, paleontology student Owain Evans created a detailed 3D reconstruction that allowed the team to analyze its structure.
"This specimen has been referred to many times in scientific papers, but it had yet to be successfully identified," Evans said.
"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. It is different from all other dinosaurs from around that time, and requires a distinctive name."
Professor Michael J. Benton, senior author of the study, said the digital models revealed striking anatomical detail. "The natural molds of the inner and outer faces of the jawbone show amazing detail -- every groove, ridge, tooth, and even the serrations along the edges of the teeth," he said.
The reconstruction also revealed the animal's surprising scale. The preserved section of jaw measures 28 centimeters, but it represents only the front half. The full jaw likely reached 60 centimeters, suggesting a dinosaur measuring 5 to 7 meters in length.
"Most of which [Triassic theropods] were half the size or smaller," Evans said. "This is unusually large for a Triassic theropod."
Analysis of the reconstructed anatomy confirmed that the fossil belonged to a theropod, a carnivorous dinosaur. The specimen has unique dental features and appears to sit near the evolutionary roots of both major theropod groups: Coelophysoidea and Averostra.
Cindy Howells, curator at the National Museum of Wales, said the discovery highlights the ongoing value of historic collections. "These historical specimens are vitally important in paleontology and often yield new and exciting results," she said.
Howells noted that Wales holds several rare Triassic fossil beds, raising the prospect of more discoveries. "The re-description of Newtonsaurus cambrensis once again highlights the significance of Wales in paleontological research," she said. "There might very well be another dinosaur waiting to be discovered."