Middle Cambrian molluscs of 'Australian' aspect from northern Siberia

An assemblage of silicified helcionelloid molluscs is described from the Kuonamka Formation (Middle Cambrian Amgan Stage) of the Bol'shaya Kuonamka and Malaya Kuonamka rivers, northern Anabar Shield, northern Siberia. In addition to the new genera Kuonamkaella and Anabaroconus, the assemblage contains species of Yochelcionella, Eotebenna, Pseudomyona, and Protowenella. These latter genera were previously unknown from the Middle Cambrian of Siberia and indicate a strong affinity with coeval molluscan faunas from the Australian Middle Cambrian. The fauna provides evidence for close palaeogeographic links to East and West Gondwana, Baltica, and Laurentia during the Middle Cambrian, and facilitates biostratigraphic correlation between these crustal blocks.