Treptichnus (formerly named Phycodes, Manykodes by J. Dzik,[2] and also known as Trichophycus[3]) is the preserved burrow of an animal.

[1] Treptichnus pedum has a fairly complicated and distinctive burrow pattern: along a central, sometimes sinuous or looping burrow it made successive probes upward through the sediment in search of nutrients, generating a trace pattern reminiscent of a fan or twisted rope.

[8] Since only its burrows have been found, it is presumed that the Treptichnus animal lacked any hard anatomical features, such as shells or bones.

[9] Despite this lack of fossil evidence, surface trails produced by modern priapulid worms exhibit the same probing morphology as Treptichnus, suggesting a close anatomical relationship between the trace-maker and modern priapulids.

[10] The name Treptichnus pedum means "turned trail (Greek) of feet (Latin)".