A new middle Cambrian radiodont from North China: Implications for morphological disparity and spatial distribution of hurdiids
Abstract Hurdiidae, a clade of Radiodonta that has attracted widespread attention in recent years, is notable for their massive tripartite cephalic carapace and a wide variety of feeding habits. Although the Hurdiidae has a cosmopolitan distribution in the Cambrian, their Miaolingian occurrences are restricted to Laurentia. Here we describe a new hurdiid radiodont, Cordaticaris striatus gen. et sp. nov., based on well-preserved specimens from the middle Cambrian (Miaolingian, Drumian) Zhangxia Formation in Shandong Province, North China. This new taxon is characterized by a heart-shaped central element with linear ornament, frontal appendages equipped with nine blade-like endites including seven subequal elongate endites, a node-bearing ‘peytoia’-type oral cone, and a trunk covered with rows of setal structures. Cordaticaris not only enriches the taxonomic diversity of Hurdiidae, but also further documents the great morphological disparity of hurdiid sclerotized body elements. The discovery of soft-bodied fossils in the Zhangxia Formation also stresses the great potential of the Miaolingian strata of North China for the preservation of non-biomineralized organisms.