A preliminary brachiopod biostratigraphy for the Lower Cambrian of the Flinders Ranges, South Australia

Detailed sampling of key Lower Cambrian successions in eastern South Australia (Stuart Shelf, Flinders Ranges and Yorke Peninsula) combined with investigation of previously unstudied shelly fossil collections belonging to the late Brian Daily has revealed a plethora of exquisitely preserved, previously undocumented, organophosphatic and calciate brachiopods from this region. These new assemblages provide new data for a prelimianary biostratigraphic “biozonation” for the Lower Cambrian succession of South Australian based on brachiopods. Whilst much work needs to be completed, four distinct brachiopod biozone assemblages can be recognised in the Lower Cambrian succession of South Australia. The oldest assemblage, dominated by the cryptotretid Askepasma occurs in pre-trilobitic (mid Atdabanian) successions of the Wilkawillina and Wirrapowie limestones. The top of the Askepasma assemblage zone is broadly equivalent with the Abadiella huoi trilobite zone (late Atdabanian) and best represented in the Flinders Ranges, but also occurs in the Stansbury Basin and on the Stuart Shelf. The succeeding assemblages, best defined in the Stansbury Basin, are early Botoman in age and characterused by Eoobolu, Minlatonia, Eodicellomus and Kyrshabaktella. The youngest (Toyonian) assemblage, best represented in the Wirrealpa Limestone is characterised by the first acrotretid (Vandalotreta) in the South Australian sequence, along with Karathele and the calciate taxon Trematobolus wirrialpensis.