Discover thousands of bone fossils uncovered from a Cretaceous bone bed in Wyoming, USA. The tyrannosaurus rex likely fed on the remains of a platypus dinosaur species known as Edmontosaurus anectens.
Reconstruction of the life of Edmontosaurus anectens. Image credit: Dani Navarro.
“Identifying the origin of perforating lesions on fossil bones can be challenging. Many are mistakenly attributed to tooth marks without considering other potential explanations,” said Bethania Siviero, a paleontologist at Loma Linda University.
“This confusion often arises from unclear tooth mark criteria, especially when the context of the lesions is overlooked.”
“Misidentification of these marks leads to misleading interpretations about the behavior of prehistoric animals.”
“Our study critically reassesses the criteria used for identifying tooth marks in fossil bones.”
In this research, Siviero and colleagues analyzed 3,013 bones excavated from a paleontological site near Hanson Ranch Station in northeastern Wyoming, part of the Lance Formation.
The majority of these bones belonged to a single species: the large herbivorous hadrosaur, Edmontosaurus anectens.
Among the 3,013 bones, only 13 exhibited traits that resembled tooth marks.
Through meticulous analysis, including CT scans, researchers determined that one of the marks was not a bite but rather a natural anatomical feature.
Confrontation between Late Cretaceous Nanotyrannus lansensis (left) and juvenile tyrannosaurus rex individuals. Image credit: Jorge Gonzalez.
Out of the 12 bones found with authentic tooth marks, including ribs, vertebrae, radius, and ulna, the analysis revealed four unique patterns linked to two endemic species: Cuneticnus pararealm and linicnus sawtooth.
By comparing the spacing of these marks with the dental structures of known predators from the same ecosystem, researchers identified the tyrannosaurus rex as the most likely perpetrator of the bite marks.
Notably, most of the chewed bones showed no signs of healing, indicating that the animals were likely bitten before, during, or after death, pointing towards scavenging rather than active predation.
Scientists utilized the Wyoming bone bed to establish more precise scientific criteria for identifying tooth marks on fossilized bones.
“Not all features on these bones are tooth marks, making accurate identification of depressions and holes crucial,” the researchers stated.
Their findings have been published in the online journal PLoS ONE today.
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BCT Cibiero et al. 2026. Identification of Cretaceous (Maastrichtian) tooth marks on Edmontosaurus anectens bone bed from the Lance Formation, Wyoming, USA. PLoS One 21 (7): e0351939; doi: 10.1371/journal.pone.0351939
Source: www.sci.news
