Mattajacyathus ROZANOV in DEBRENNE, A. ZHURAVLEV& ROZANOV, 1989
Specimen-type: Robertocyathus arduus holotype, ROZANOV, 1969, p. 113
Systematics:
Order: AJACICYATHIDA R. Bedford& J. Bedford, 1939
Suborder: AJACICYATHINA R. Bedford& J. Bedford, 1939
Superfamily: PRETIOSOCYATHOIDEA Rozanov, 1969
Family: ROBERTOCYATHIDAE Rozanov, 1969