Description. The borings are relatively parallel sided and round in cross section, generally about 5 to 7 μm in diameter. They trace a path which varies from irregular and sharply angled to gently sinuous, the morphology probably largely dependant on the substrate type. Where colonisation is light, the borings run along the surface of the bone substrate, with the top exposed to the sediment, and continue for up to 200 μm before penetrating deeper into the interior of the substrate. Branching is bifurcate but irregular, generally every 50 to 100μm. Where the degree of boring is more intense, the original surface of the tooth is destroyed and the borings form a more irregular ramifying mass.