Article: Early Cambrian intergrowths of archaeocyathids, Renalcis, and pseudostromatolites from South Australia

Lower Cambrian life and death assemblages of late Atdabanian-Botomian age are described from the Wilkawillina Limestone of South Australia. The biota, sedimenlology, and diagenesis arc analysed to reveal an ecological succession in which archacocyalhids grew one upon another, and were overgrown by the problematic organism Renalcis, with the cavities later filled by pseudostromatolites (coniatolites). A low-latitude, littoral habitat is inferred. Examination of the unusually well-preserved archaeotryathid intergrowths suggests that their individuality was slrongly expressed, with an organization at least of sponge or coelentcrate grade. Settlement and growth of archaeocyathid juveniles was apparently controlled by substrate type, space, and light. The life assemblage provides one of the oldest examples of competitive intcrreuclions between animals.