Occurrence of Byronia Matthew and Sphenothallus Hall in the Lower Cambrian of China

Rare phosphatic tubular fossils from the Lower-Middle Cambrian Kaili Formation of Guizhou Province, southern China were originally identified as non-calcified algae or ‘worms’ (ScoleciellusLiu). Re-examination of these fossils indicates that specimens identified as non-calcified algae areSphenothallus taijiangensis n. sp., while specimens identified asScoleciellus belong to Byronia natus (Liu).Sphenothallus taijiangensis and Byronia natus from Lower Cambrian strata in the Kaili Formation are the oldest known representatives of their genera. In addition,B. natus (Liu) is the only known species ofByronia with the exception ofB. annulata Matthew (Middle Cambrian, British Columbia). Cambrovitus Mao et al., a tubular fossil from Middle Cambrian strata in the Kaili Formation, originally was classified as a hyolithid. However, the discovery of a nearly complete specimen possessing an apical attachment disk shows that Cambrovitus, like Byronia and Sphenothallus, probably was a thecate cnidarian polyp.