Salterella and Volborthella from the Early Cambrian of Spitsbergen: the evolution of agglutinating organisms during the Neoproterozoic-Cambrian transition

The co-occurrence of the small agglutinated, conical fossils Volborthella and Salterella is documented from the Lower Cambrian Tokammane Formation of Ny Friesland, Spitsbergen. Microstructural investigations of well-preserved Volborthella tenuis Schmidt (1888), collected from the fine-grained Topiggane Shale, indicate the presence of an organic cementing matrix that may have extended around the edges of the test to form an outer organic sheath. This is clearly distinct from the carbonate cements observed in specimens of Salterella maccullochi (Murchison 1859), supporting the taxonomic validity of Volborthella and Salterella. The occurrence of both these forms in this succession may indicate a biogeographic link between the Laurentian province, where both Salterella and Volborthella are found, and the Baltic and East European Platform, where only Volborthella is reported to occur. The exclusive presence of Volborthella in the older siliciclastic Topiggane Shale Member and Salterella in the younger carbonates of the Ditlovtoppen Dolomite provides both a testable age-relation between these two forms and suggests that there may be a significant facies control on their distribution. These organisms are significant in the early history of agglutinated skeletons, especially in their use of both organic and carbonate cements significantly earlier than other Paleozoic agglutinating organisms, such as the foraminifera.