18
4
November
725
739
BROMLEY, R. G. 1975. Comparative analysis of fossil and recent echinoid bioerosion. Palaeontology, 18, 4, 725–739.
R. G. Bromley One of the most abundant forms of bioerosion sculpture on Mesozoic and Cainozoic shells and other hard substrates has a pentaradiate symmetry based on a regular, stellate module consisting of five radiating grooves. Regular echinoids today, browsing on encrusting and boring organisms on hard substrates, produce identical sculpture to the trace fossil, and a common origin is suggested. The tooth scratches lose their pentaradiate orientation and become subparallel where the echinoid gnaws along edges of shells and flat pebbles; a corresponding sculpture is also encountered in the trace fossil. The pentaradiate trace fossil is designated as Gnathichnus pentax, ichnogen. et ichnosp. nov. The Palaeontological Association (Free Access)