Protichnites

Protichnites is a genus of trace fossil consisting of the imprints made by the walking activity of arthropods. It is likely that more than one type of arthropod was responsible for these tracks. Euthycarcinoids, aglaspidids (see Aglaspida) and eurypterids are possible contributors. Protichnites consists of two rows of tracks and a linear depression between the two rows. This depression, which may be broken, set at an angle, and of varying width and depth, is thought to be the result of a dragging tail. The structures bearing this name were typically made on the tidal flats of Paleozoic seas, but similar ones extend into the Cenozoic. Its occurrence in late Cambrian sandstones of Canada and northern United States is evidence of some of the first life on land.