Complex marine trace fossils

Structurally elaborate burrow systems deserve special attention from ichnologists as the products of complex, variable behavior. Ichnogenera such as Zoophycos, Paleodictyon and Phymatoderma in some cases record deliberate restructuring of habitats, modulation of disturbances, and active control of food supplies. Thus they cannot be accommodated in the traditional ethologic classification of trace fossils.