This Protichnites comes from the Krukowski Quarry, believed to be an outlier of the Mount Simon Sandstone. This quarry is currently under study as perhaps containing Ichnofossils of the earliest animals to venture ashore during the Middle Cambrian. Among the different trackway fossils found in this quarry (including Diplichnites and Climactichnites), Protichnites is the rarest both in terms of dispersion and absolute numbers. The sandstone slab here lacks ripples, suggesting that the tracks were made on a sand flat well above the tide, rather than underwater. This, in turn, suggests that the animal which made Protichnites tracks could have been one of the Earth's first air-breathing animals.

Some of the mystery of Protichnites trackways is just being cleared up as, after more than a decade, the very first body fossils of a putative Protichnites track maker have at last been discovered in the Krukowski quarry. The creatures that were discovered in a single dessication zone during the summer of 2004 have affinity to one of the most problematic groups of Arthropods, the Euthycarcinoids. The euthycarcinoids that are known from 13 species from Upper Cambrian or Lower Silurian-Middle Triassic from Argentina, Western Australia, Europe (e.g., the Rhynie chert) and the Mazon Creek in Illinois (Vacarri, 2004). But it is only in the Argentina and Wisconsin sites that the Protichnies trackways are also found. Expect a publication within the next year that adds the 14th and the oldest species to the group from the Krukowski quarry. Thus, the Krukowski Euthycarcinoid may emerge as the oldest land-based animal fossil in the entire fossil record.

This smaller particular specimen contains a very high density of both footprints and tail tracks (some of which exhibit curvature), and is totally natural without any staining.