Specimens of the Middle Cambrian benthic graptolite Sphenoecium have been discovered at two levels in the Alum Shale Formation at Krekling, Oslo Region, Norway. The material originated from an interval in the Goniagnostus nathorsti Biozone (upper Drumian stage of the Cambrian System) and represents only the second record of this genus from Norway. The specimens show the tubarium development more clearly than the type material ofSphenoecium mesocambricus, which was found in the same general region. Sphenoecium mesocambricus has a tubarium with slender creeping tubes,branching at close distances, and considerably widening erect thecal tubes with straight apertures. A much more slender specimen belonging to the same genus was also found, but cannot be referred to a described species.
The benthic graptolite Sphenoecium mesocambricus (Öpik, 1933) from the Middle Cambrian of Krekling, Oslo Region, Norway