Trilobites and other fossils from the Viar River section (Cambrian Series 2, Stage 4), SW Spain

Abstract

The Marianian (Cambrian Series 2) fossil assemblage of the Viar River section is here reviewed and updated, based on previous collections and new collected specimens. This section is located in southern Badajoz, southwestern Spain, and belongs to the northern branch of the Cambrian outcrops of the Ossa-Morena Zone, southwestern Iberian Massif. Specimens studied occur in the ‘Benalija beds’ of the Viar-Benalija Block. The fossil assemblage from this section is composed of the trilobites Protaldonaia morenica, Triangulaspis fusca Chelediscus garzoni and Serrodiscus bellimarginatus, the brachiopod Sibiria? sp. and the helcionellid mollusc Marocella morenensis. Protaldonaia is revised, and its classification as a subgenus of Protolenus is rejected. The species T. fusca and C. garzoni are here described and illustrated for the first time from this section. Also, new data show that C. garzoni is more broadly distributed throughout the Cambrian of the Ossa-Morena Zone. This fossil assemblages suggests a late Marianian age according to the Iberian regional biostratigraphic scheme, and it can be tentatively correlated with the early Cambrian Stage 4 at international level.