Occurrence of the eudemersal radiodont Cambroraster in the early Cambrian Chengjiang Lagerstatte and the diversity of hurdiid ecomorphotypes

Radiodonts are a diverse clade of Lower Palaeozoic stem-group euarthropods that played a key role in the emergence of complex marine trophic webs. The latest addition to the group,Cambroraster falcatus, was recently described from the Wuliuan Burgess Shale, and is characterized by a unique horseshoe-shaped central carapace element. Here we report the discovery ofCambrorastersp. nov. A, a new species from the Cambrian Stage 3 Chengjiang Lagerstatte of South China. The new occurrence ofCambrorasterdemonstrates that some of the earliest known radiodonts had already evolved a highly derived carapace morphology adapted to an essentially eudemersal life as sediment foragers.