"Cathaymyrus" is related to "Pikaia", another cephalochordate from the Burgess Shale. Palaeobranchiostoma hamatotergum is an extinct cephalochordate from the Early Permian-aged Whitehill Formation in South Africa. A digestive organ called the hepatic caecum is found in the cephalochordate amphioxus, or lancelet. Homologues of the IF protein have been noted in an invertebrate, the cephalochordate "Branchiostoma". Recently, a different cephalochordate fossil ("Yunnanozoon") has been found in south China.