A middle Cambrian fauna of skeletal fossils from the Kuonamka Formation, northern Siberia

Abstract

An assemblage of mineralized skeletal fossils containing molluscs, hyoliths, chancelloriids, protoconodonts, lobopods, paleoscolecids, bradoriids, echinoderms and hexactinellid sponges is described from the middle Cambrian part of the Kuonamka Formation, exposed along the Malaya Kuonamka and Bol'shaya Kuonamka rivers, northern Siberian Platform. The sampled succession is attributed to the Kuonamkites and lower Tomagnostus fissus–Paradoxides sacheri biozones of the Amgan Stage of Siberia, correlated with Series 3, Stage 5—lower Drumian Stage of the IUGS chronostratigraphical scheme for the Cambrian. This work complements descriptions of molluscs from the same samples published by Gubanov et al. (2004) with additional material. It contains forms in common with coeval faunas from Australia, China, Western Gondwana, Avalonia, Laurentia and Baltica, increasing potential for global biostratigraphic correlation and understanding of palaeogeographic connections.

Key words:

• Middle Cambrian
• Siberia
• skeletal fossils
• biostratigraphy
• palaeobiogeography

Acknowledgements

We thank Shane Pelechaty, and the late Anatolij V. Val'kov and Vladimir V. Missarzhevsky for assistance in the field. Our work was financially supported by grants from the Royal Swedish Academy of Sciences (KVA) and the Swedish Research Council (NFR, now VR). Artem Kouchinsky is also supported from the NordCEE (Nordic Center for Earth Evolution) project (Danish National Research Foundation (Danmarks Grundforskningsfond) grant to Prof. Donald Canfield. Sébastien Clausen is supported by ANR project JC07-194555 financed by CNRS-USAR. We thank Stefan Ohlsson (Stockholm) for technical assistance with sample preparation. John Peel acknowledges support from the Swedish Research Council (VR).