Sophisticated particle-feeding in a large Early Cambrian crustacean

A fancy eater Modern crustaceans show a wide diversity of feeding strategies, evidenced by the complex array of mouthparts and appendages required to handle food of different sizes and types. Back in the Cambrian Period, however, things were much simpler — or so it was thought.Now, a Cambrian crustacean capable of selective, efficient shrimp-like feeding among the otherwise messy-feeding and archaic-looking Cambrian arthropods has been described. This relatively large creature could manipulate fine food particles more than 100 million years before the major expansions of large-bodied particle-handling crustaceans, emphasizing the role of ecological context in driving adaptive radiations. Most Cambrian arthropods employed simple feeding mechanisms requiring only low degrees of appendage differentiation. But now, a sophisticated feeding apparatus from a Cambrian crustacean is described, showing that relatively large creatures were capable of manipulating fine food particles. Most Cambrian arthropods employed simple feeding mechanisms requiring only low degrees of appendage differentiation 1 , 2 , 3 . In contrast, post-Cambrian crustaceans exhibit a wide diversity of feeding specializations and possess a vast ecological repertoire. Crustaceans are evident in the Cambrian fossil record, but have hitherto been known exclusively from small individuals with limited appendage differentiation 4 . Here we describe a sophisticated feeding apparatus from an Early Cambrian arthropod that had a body length of several centimetres. Details of the mouthparts resolve this taxon as a probable crown-group (pan)crustacean, while its feeding style, which allowed it to generate and handle fine food particles, significantly expands the known ecological capabilities of Cambrian arthropods. This Early Cambrian record predates the major expansions of large-bodied, particle-handling crustaceans by at least one hundred million years 5 , 6 , emphasizing the importance of ecological context in driving adaptive radiations.