Xiazhuangocaris
Xiazhuangocaris is an extinct genus of bivalved arthropod known from the Cambrian aged Chengjiang Biota of Yunnan, China. Only a single specimen (NIGP 172765) is known, around  long, which only preserves the anatomy of the carapace and the trunk. The bivalved carpace has a pronounced pair of notches at its front, as well as a posterior notch at its rear. The body had at least 13 tergite-pleurite rings, which terminate in a pair of rounded caudal rami, which are fringed with setae. The describing authors interpreted the taxon as a member of Hymenocarina, which contains other Cambrian bivalved arthropods. References 

Hymenocarina
Cambrian arthropods