500M-Year-Old 'Alien Fish Taco' Was Among First Creatures with Jaws

A 500-million-year-old fossil of an arthropod named Odaraia alata, discovered in the Burgess Shale fossil site, has provided insights into the early evolution of creatures with jaws. This creature, resembling an "alien fish taco," had bulging eyes, a rudderlike tail, and 30 pairs of spiny limbs. It measured about 20 centimeters in length and was buried under sediment, preserving its remains for study. Recent research, led by Alejandro Izquierdo-López from the University of Toronto, focused on the fossil's mandibles, which are significant in understanding the Cambrian explosion, a period marked by a rapid increase in diverse life forms. The study suggests that the evolution of mandibles allowed these creatures to efficiently break down food, giving them a competitive advantage over other organisms. Odaraia's size also contributed to its feeding efficiency, enabling it to roam freely in the ocean rather than being confined to small communities. The research identified tiny spines on its legs that likely functioned as a filter-feeding mechanism, allowing it to capture small particles from the water. Additionally, the fossil features a unique trident-shaped tooth, the purpose of which remains a mystery. This discovery highlights the evolutionary significance of Odaraia alata in the development of modern animal groups, particularly those with mandibles, and raises questions about its feeding strategies and ecological role during its time.