Remember when? Deciphering Ediacaran-Cambrian Metazoan behaviour and temporal memory using fossil movement paths

Abstract: Evaluating the timing and trajectory of sensory system innovations is crucial for understanding the increase in phylogenetic, behavioural, and ecological diversity during the Ediacaran-Cambrian transition. Elucidation of sensory adaptations has relied on either body-fossil evidence based on anatomical features or qualitative descriptions of trace-fossil morphology, leaving a gap in the record of sensory system innovations between the development of basic sensory capacities and that of more advanced sensory organs and brains. Here, we examine fossil movement trajectories of Ediacaran and Cambrian grazers for the presence of autocorrelation. Our analysis reveals a lack of temporal correlation in the studied Ediacaran trajectories and its presence in both analysed Cambrian trajectories, indicating time-tuned behaviours were in place by the early Cambrian. These results support the Cambrian Information Revolution hypothesis and indicates that increases in cognitive complexity and behavioural strategies were yet another important evolutionary innovation that occurred during the Ediacaran Cambrian transition.