1. Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK

Correspondence to: Thomas H. P. Harvey¹ Correspondence and requests for materials should be addressed to T.H.P.H. (Email: thar04@esc.cam.ac.uk).

Abstract

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 differentiation⁴. 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.