Iguanodon shinbone growth may be first evidence of an infected skin ulcer in a dinosaur

Researchers examining a fossilized shinbone of Iguanodon bernissartensis have identified what may be the first documented case of an infected skin ulcer in a dinosaur. The discovery, detailed in a study published in Royal Society Open Science, suggests that the ancient herbivore suffered from a condition akin to modern-day bacterial infections affecting the skin and underlying bone. The analysis focused on a 17.4-centimeter (6.9-inch) overgrowth along the middle portion of the tibia, covering approximately 17% of the bone’s length. This abnormal growth was observed in one of two fossilized remains of Iguanodon recovered from the Mas de la Parreta quarry in Morella, eastern Spain. The specimen, designated CMP-11/8, was examined using high-resolution 3D scanning techniques typically used in medical imaging. These scans allowed the research team to analyze the internal structure of the bone and rule out other potential causes such as fractures, tumors, or degenerative diseases. The findings indicate that the overgrowth likely resulted from an infected skin ulcer that had progressed close enough to the bone to stimulate reactive bone growth. The lesion did not penetrate the central cavity of the bone, suggesting that the damage originated in the surrounding soft tissues rather than within the bone itself. This pattern aligns with how modern humans respond to chronic wounds, when an open sore develops near the bone, it can lead to inflammation and the formation of dense, irregular bone tissue. The study authors propose that the condition would have been painful, particularly during movement. As noted in the paper, "The progression of ulceration toward the periosteum of the bone may have caused persistent pain, which was aggravated by normal walking and muscle pressure." This implies that the affected individual likely experienced discomfort that could have impacted its mobility or overall health. While bone abnormalities have been previously documented in dinosaur fossils, this instance appears to represent a novel form of pathological response linked to a bacterial infection. Researchers emphasize that this is the first recorded case of a polymicrobial ulcer in dinosaur remains, offering new insights into the types of diseases that may have afflicted prehistoric creatures. The discovery adds to the growing body of evidence that ancient organisms were susceptible to conditions similar to those seen in modern animals. By studying such anomalies in fossilized remains, paleontologists can better understand the biological challenges faced by extinct species and potentially draw parallels with contemporary medical conditions. The research was conducted by a team led by Javier Salas-Herrera, with contributions from experts in anatomy, pathology, and paleontology. Their work underscores the importance of interdisciplinary approaches in uncovering the complexities of life in the distant past. The study highlights how technological advancements in imaging and data analysis continue to refine our understanding of evolutionary history.