A new radiodont from the lower Cambrian (Series 2 Stage 3) Chengjiang Lagerstätte, South China informs the evolution of feeding structures in radiodonts

Radiodonts, a diverse clade of early Palaeozoic stem-group euarthropods, have provided critical information for understanding the evolution of this phylum, and were important constituents of marine ecosystems at this time. The well-known Chengjiang Lagerstätte (Cambrian Stage 3, <i>c</i>. 518 Ma) has yielded the highest known diversity of radiodonts of any Cambrian Konservat-Lagerstätten, and represents a crucial deposit for radiodont research. One important but generally overlooked Chengjiang radiodont taxon, previously identified as <i>Anomalocaris</i> sp. or Radiodont C, is herein designated as the type species of a new monotypic genus, <i>Shucaris ankylosskelos</i> gen. et sp. nov., based on dozens of specimens. <i>Shucaris</i> is distinctive for its combination of several characters, including the presence of two pairs of endites on its proximal-most claw podomere, posteriorly inward curved endites on claw podomeres 2–6, and, most strikingly, the coexistence of gnathobase-like structures and an oral cone. New material of <i>Ramskoeldia consimilis</i> records the first known oral cone in this species, confirming that oral cones and gnathobase-like structures co-occur in multiple radiodont taxa. Phylogenetic analyses retrieve <i>Shucaris</i> as either an early diverging member of Anomalocarididae or as sister to the clade Anomalocarididae + Amplectobeluidae. Moreover, our phylogenetic analyses also support the divergence between hurdiid and non-hurdiid radiodonts. https://zoobank.org/urn:lsid:zoobank.org:pub:6989C81B-06B2-4AED-8297-3B200A6F8D69