Ancient shrimplike creature identified as the quintessential apex predator of its time by scientists

Scientists previously believed that an ancient shrimp-like creature called Anomalocaris canadensis was the ultimate apex predator of its time due to its armoured mouth and appendages growing out of its head.

This sea creature gained a fearsome reputation as researchers thought it was responsible for crushing and scarring the fossilized skeletons of trilobites, early hard-shelled invertebrates that vanished during a mass extinction before the era of dinosaurs.

Measuring around 2 feet long (0.6 meters), Anomalocaris canadensis was one of the largest marine animals that existed 508 million years ago during the Cambrian period, a crucial point in Earth’s history marked by a surge in biodiversity and the emergence of major animal groups.

Lead author Russell Bicknell, a postdoctoral researcher at the American Museum of Natural History, and his collaborators from the United Kingdom, Germany, China, and Switzerland reconstructed the creature in 3D using computer modeling and a well-preserved but flattened fossil found in the Burgess Shale formation in the Canadian Rockies.

Contrary to earlier research suggesting that Anomalocaris had a mouth incapable of processing hard food, Bicknell and his colleagues focused on whether the creature used its long, spiny appendages to chew trilobite prey. They examined present-day whip spiders and whip scorpions, which have similar appendages for grasping prey, as analogues.

Through their study, the team demonstrated that the segmented appendages of Anomalocaris were capable of grasping and had the flexibility to stretch out. However, their analysis revealed that the creature was weaker than previously believed and “incapable” of crushing hard-shelled prey with its structures.

The findings, published in the journal Proceedings of the Royal Society B, challenge previous assumptions about the creature’s feeding habits and highlight the complexity of Cambrian food webs.

Bicknell commented that the dynamics of the Cambrian period’s ecosystems were likely more intricate than previously thought, suggesting that Anomalocaris and other species interacted in a more complex manner rather than a simple predator-prey relationship.