Healed Fang Wound on 520-Million-Year-Old Apex Predator

Researchers have discovered a unique 520-million-year-old fossil from the Cambrian Period featuring a healed bite wound on a swimming flap of Amplectobelua symbrachiata, an apex predator belonging to the radiodont group. Found in the Yu'anshan Formation in China, this rare fossil provides direct evidence of prehistoric predation and aggressive interactions among ancient marine apex predators. X-ray fluorescence mapping and the presence of a dark melanisation band around the W-shaped injury confirm that the wound occurred while the organism was alive and successfully healed. The researchers, including Stephen Pates and Kunsheng Du, argue that the specific W-shape and location of the trauma strongly indicate a fang attack from another predator, potentially a rival radiodont or even a member of the same species. While alternative hypotheses such as moulting damage have been suggested by experts like Joe Moysiuk, the morphological characteristics of the injury heavily favor a predation event. This discovery offers unprecedented insight into the fierce ecological pressures and survival struggles in early marine ecosystems. This finding represents a significant milestone in paleontological research because soft-tissue fossils of radiodonts are exceptionally rare due to their delicate swimming flaps. Unlike trilobites, which frequently display healed injuries owing to their hard exoskeletons and abundance in the fossil record, finding similar evidence in soft-bodied radiodonts is unprecedented. The study bridges critical knowledge gaps regarding predator-prey dynamics and intraspecific competition during the Cambrian explosion. Paleontologists and evolutionary biologists can utilize these findings to better model ancient marine food webs and the intensity of evolutionary pressures 520 million years ago. Future excavations in exceptional fossil preservation sites like the Yu'anshan Formation may yield additional specimens to further clarify the frequency of non-lethal predatory attacks in early animal communities.