First occurrence of the problematic vetulicolian Skeemella clavula in the Cambrian Marjum Formation of Utah, USA

Abstract

The Cambrian Marjum Formation of western Utah (USA) preserves a diverse soft-bodied fauna from the upper Drumian that is slightly younger than the well-known Burgess Shale. While the Marjum is dominated by arthropods, animals belonging to a variety of phyla have been found. Here, we document the second occurrence of the rare, enigmatic taxon Skeemella clavula, which was previously thought to be restricted to the Pierson Cove Formation of the Drum Mountains. The occurrence in the Marjum represents a new preservational setting, as well as a slightly younger deposit. The new specimens also expand the number of known specimens to three. In addition, they improve understanding of the morphology of this representative of the problematic phylum Vetulicolia.