Hemithalamocyathus TING, 1937
Specimen-type: Archaeocyathus sibiricus lectotype, TOLL, 1899, pl. 6, fig. 5
Systematics:
Order: AJACICYATHIDA R. Bedford& J. Bedford, 1939
Suborder: AJACICYATHINA R. Bedford& J. Bedford, 1939
Superfamily: ANNULOCYATHOIDEA Krasnopeeva, 1953
Family: ANNULOCYATHIDAE Krasnopeeva, 1953