79-9 Assessing the 3D Morphology of the Ediacaran-Cambrian Index Trace Fossil Treptichnus pedum

Abstract:

As the oldest-known example of complex, three-dimensional burrowing, the trace fossil Treptichnus pedum is used to denote the transition to more 'modern' oceans and the beginning of the Phanerozoic, thus making it the only trace fossil used to mark a stratigraphic boundary. While thought to represent the systematic probing of a vermiform organism in search of nutrients, our understanding of the 3D structure of T. pedum has historically been pieced together from varying 2D expressions and experimental recreations with potential modern analogues, and non-destructive imaging techniques have been largely stymied by the low contrast between its constituent materials. Here I present an exceptional specimen of T. pedum from the National Museum of Natural History's Preston Cloud collection and discuss how CT and synchrotron imaging, as well as deep learning image segmentation models, are allowing for novel assessments of both the three-dimensional structure(s) and potential behavioral implications of this critical index fossil.

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