Duck-billed dinosaur had a tumor on its jaw

A reconstruction of the young Telmatosaurus. (Credit: Mihai Dumbravă, color added)

Scientists have discovered the first tumorous facial swelling in a fossil on the jaw of a primitive duck-billed dinosaur called Telmatosaurus transsylvanicus.

“This discovery is the first ever described in the fossil record and the first to be thoroughly documented in a dwarf dinosaur,” says Kate Acheson, a PhD student at the University of Southampton.

Telmatosaurus transsylvanicus
A reconstruction of the young Telmatosaurus. (Credit: Mihai Dumbravă, color added)

“Telmatosaurus is known to be close to the root of the duck-billed dinosaur family tree, and the presence of such a deformity early in their evolution provides us with further evidence that the duck-billed dinosaurs were more prone to tumors than other dinosaurs.”

The hadrosaur fossil, estimated to be approximately 69-67 million years old, was discovered in the “Valley of the Dinosaurs” in the Haţeg County Dinosaurs Geopark in Transylvania, western Romania, a UNESCO site.

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“It was obvious that the fossil was deformed when it was found more than a decade ago but what caused the outgrowth remained unclear until now,” says Zoltán Csiki-Sava of the University of Bucharest, Romania, who led the field trip that uncovered the fossil. “In order to investigate the outgrowth, our team was invited by SCANCO Medical AG in Switzerland to use their Micro-CT scanning facilities and to ‘peek’ unintrusively inside the peculiar Telmatosaurus jawbone.”

The scans suggested that the dinosaur suffered from a condition known as an ameloblastoma, a tumorous, benign, non-cancerous growth known to afflict the jaws of humans and other mammals, and some modern reptiles.

Bruce Rothschild of the Northeast Ohio Medical University and a worldwide expert in paleopathology studied the Micro-CT scans. “The discovery of an ameloblastoma in a duck-billed dinosaur documents that we have more in common with dinosaurs than previously realized,” he says. “We get the same neoplasias.”

“It was expected, due to the impoverished nature of the fauna, that our project to investigate diseases of the bone in the dwarf dinosaurs of the Haţeg County Dinosaurs Geopark would reveal some interesting results, but the discovery of a rare modern tumoral condition, and one that is so far unique in the fossil record, was a wonderful surprise,” explains Mihai Dumbravă, PhD student at Babeş-Bolyai University in Cluj-Napoca, Romania, and lead author of the study in the journal Scientific Reports.

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It is unlikely that the tumor caused the dinosaur any serious pain during its early stages of development, just as in humans with the same condition, but researchers can tell from its size that this particular dinosaur died before it reached adulthood.

Since its preserved remains consist of only the two lower jaws, no one can ascertain its cause of death. The researchers were left wondering, nonetheless, whether the presence of the ameloblastoma could have contributed to its death.

“We know from modern examples that predators often attack a member of the herd that looks a little different or is even slightly disabled by a disease,” says Csiki-Sava. “The tumor in this dinosaur had not developed to its full extent at the moment it died, but it could have indirectly contributed to its early demise.”

SCANCO Medical AG, CNCS, and POSDRU supported the work, as did the University of Bucharest, which oversees the management of the Hațeg County Dinosaurs Geopark.

Source: University of Southampton