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The Phanerozoic aftermath of the Cambrian information revolution: sensory and cognitive complexity in marine faunas

Citation

Hsieh, Shannon; Plotnick, Roy; Bush, Andrew (2021), The Phanerozoic aftermath of the Cambrian information revolution: sensory and cognitive complexity in marine faunas, Dryad, Dataset, https://doi.org/10.5061/dryad.5x69p8d43

Abstract

The Cambrian information revolution describes how biotically-driven increases in signals, sensory abilities, behavioral interactions, and landscape spatial complexity drove a rapid increase in animal cognition concurrent with the Cambrian radiation. Here, we compare cognitive complexity in Cambrian and post-Cambrian marine ecosystems, documenting changes in animal cognition after the initial Cambrian increase. In a comparison of Cambrian and post-Cambrian Lagerstätten, we find no strong trend in the proportion of genera possessing two types of macroscopic sense organs (eyes and chemoreceptive organs such as antennae, feelers or nostrils). There is also no trend in general nervous system complexity. These results suggest that sophisticated information processing was already common in early Phanerozoic ecosystems, comparable with behavioral evidence from the trace fossil record. Most taxa capable of complex information processing in Cambrian ecosystems were panarthropods, whereas mollusks and chordates made up larger proportions afterward. In both the Cambrian and present day, ecological occupation of diverse habitat tiers and feeding modes are possible with even simple nervous systems, but ecological lifestyles requiring rapid, regular movement are almost exclusively associated with brain-bearing taxa, suggesting a connection with fast information processing abilities and bodily responses. The overall rise in cognitive sophistication in the Cambrian was likely a unique event in the history of life, although some lineages subsequently developed more elaborate sensory systems and/or larger brains.

Methods

The cells within the data that contain "?" represent uncertain anatomical coding or taxonomic assignment.