Cancer, tumor, and infectious conditions are ancient pathologies. This is the conclusion of a study carried out by Benjamin Jentgen-Ceschino, Ph.D. student at the EDDyLab (Geology Research Unit) of the University of Liège, in collaboration with researchers from the Vrije Universiteit Brussel (VUB). The research adds to existing data on bone paleopathology, particularly in dinosaurs. To do so, the research team studied bone samples from sauropods, the group including the longest and heaviest dinosaurs, which were collected during a previous research project by Koen Stein, paleontologist at the VUB and co-author of the study.
"When I sampled these dinosaur bones in 2008 for my own doctoral research on sauropod bone growth, I noticed that they featured aberrant bone tissue, but I never had time to describe and analyse them in detail. It is through Benjamin's painstaking work, who analysed tens of medical and veterinary cases that the team managed to narrow down the potential causes of these diseases," said Stein.
The researchers studied thoroughly bone tissue samples from individuals of primitive sauropod species, namely Spinophorosaurus nigerensis and cf. Isanosaurus, both of them revealing patterns of development likely being the expression of a cancer, tumor or virus.
“We observed different types of conditions," said Jentgen-Ceschino, first author of the publication. "In a bone sample of cf. Isanosaurus from the Early Jurassic (c. 200 million years ago) of Thailand, we see no further growth of the animal beyond growth of thin spicules on the bone surface. This means that the animal died shortly afterwards.”
These spicules—thorn-shaped bone tissue with abnormal perpendicular development to the outer surface of the bone—are typically associated with malignant bone tumors and thus fit the hypothesis of a malignant bone cancer in this individual.
The team also report on abnormal bone spicules in a sample of bone tissue from the dinosaur Spinophorosaurus recovered from Jurassic rocks of Niger, similar to those found in cf. Isanosaurus. But this time, the animal survived the pathology, and continued to grow and produce normal bone tissue afterward.
“It may have been a reaction to a benign tumor or a viral infection, but the rest of the skeleton of this particular individual also shows several other pathologies, indicating this Spinophorosaurus suffered from different types of trauma during its lifetime," said Jentgen-Ceschino.
This study, which demonstrates that bone pathologies such as bone cancers or infections are conditions that have existed and spread to a wide range of organisms for hundreds of million years, is crucial as the fossil record cancers are scarce.
“This study also suggests that many fossil pathologies have probably been left unnoticed so far as the two dinosaurs we sampled did not show any clear external signs that could have predicted the existence of the pathologies since the pathological tissues were actually hidden in the bone," concludes Valentin Fischer, director of the EDDyLab.
Further studies of this type could perhaps reveal the onset of other bone diseases earlier than previously thought and contribute to a catalog of pathologies preserved in fossil bone tissues.
Republished courtesy of University of Liège. Photo: Illustration of Spinophorosaurus drawn by Joshua Knüpp. Credit: University of Liège.