Sphenothallus from the Furongian (Cambrian) of Scandinavia

Abstract

Sphenothallus, a Palaeozoic genus of uncertain affinity, possibly a hydrozoan, is reported from the Furongian (Cambrian) of Scandinavia. This is the only known occurrence of the genus in Cambrian rocks outside of China, western North America and Bohemia, and also the first report of Sphenothallus in the Cambrian–Ordovician of Baltica. The material is from the upper Furongian (upper Protopeltura and lower Peltura superzones) of Mount Kinnekulle, Västergötland, south-central Sweden. It consists of elongated, slightly tapering, shiny black phosphatic tubules. Scanning electron microscope photographs confirm paired internal longitudinal thickenings, typical of the genus, on opposite sides of the central lumen. The presence of the Swedish material in a low-energy, dysoxic facies is consistent with most previous occurrences.

Keywords::

• Sphenothallus
• Alum Shale Formation
• Furongian
• Cambrian
• Västergötland
• Sweden

Acknowledgements

The authors thank Nicola Cayzer for assistance with scanning electron microscopy, and Yvonne Cooper for photographic work. The authors also thank the journal reviewers, Heyo Van Iten and an anonymous reviewer, for useful comments on the manuscript.