Experimental production of animal trace fossils, with a discussion of allochthonous trace fossil producers

We present a new method of producing animal traces at the sand-mud interface by taking advantage of the low viscosity of polyester resins. We illustrate its applicability with traces made by the amphipod crustacean Haustorius arenarius. When introduced into a tank with a relatively thin sand-cover this amphipod produces bilobed traces along the sand-mud interface. From what was previously known of the behaviour of haustoriid amphipods this trace is unexpected. We suggest that the haustoriids attempted to burrow deeper into the sediment but that the mud formed a barrier. These experiments may represent a naturally occurring scenario with a high preservational potential and such ‘barrier prospecting traces’ should occur in the fossil record.