Rusophycus

Rusophycus is a trace fossil allied to "Cruziana". "Rusophycus" is the resting trace, recording the outline of the tracemaker; "Cruziana" is made when the organism moved. The sculpture of "Rusophycus" may reveal the approximate number of legs that the tracemaker had, although striations (scratchmarks) from a single leg may overlap or be repeated.
Both "Rusophycus" and "Cruziana" are typically associated with trilobites but can also be made by other arthropods. "Rusophycus" is known from sediments dating to the earliest Cambrian Period (somewhat before the first appearance trilobite fossils), and from the Triassic Period (after the Permian extinction of trilobites), indicating that other producers could make the trace.