Traces of Insect Activity at Cooper's D Fossil Site (Cradle of Humankind, South Africa)

This study constitutes the first comprehensive description and analysis of trace fossils produced by insects on bone from a faunal assemblage in the Cradle of Humankind, South Africa. A total of 9,500 bone fragments from Cooper's D were visually inspected for evidence of insect trace fossils. Fifty-three specimens with insect traces were identified and analysed using optical microscopy at low magnifications. Analysis revealed frass and coprolites preserved on some bones, and nine morphologically distinctive traces. Circular boreholes associated with a crescent-shaped excavation are attributed to a new ichnogenus Munitusichnus pascens, while ellipsoid surface borings (pupation chambers) are assigned to a new ichnospecies Cubiculum cooperi. Evidence suggests that traces were produced by more than one agent at different stages during the taphonomic process. Modification either took place whilst bones were sub-aerially exposed, at the point of final deposition, or post-burial of the remains. Munitusichnus pascens and Cubiculum cooperi represent the first ichnotaxa in bone from the Cenozoic of African.