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
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
taxonomic identity of Protichnites makers from the Mount Elk Group
is unknown. Aglaspids, crustaceans, chelicerates or members of a
euryipterid stem group are among the arthropods that have been considered.
particular specimen is the most recent Protichnites species first
described in April 2009. Hagadorn and Seilacher hypothsize that
the Protichnites eremita shown here was formed by so called hermite
arthropods walked the Cambrian shore partially inside shells of
other animals. This hermite crab-like strategy might have afforded
the protection of a humid chamber that mitigated dessication of
gills in the alien subaerial environment. The defining characteristic
of Protichnites eremita is tail impressions that are angled to the
left side of the track, as would be formed by a coiled shell intermittently
scraping the sediment substrate. The presence of abundant sand stromatolites
both above and below the tracks suggest that cyanobacterial mats
mediated the preservation of Protichnites eremita.
our knowledge, this is the only Protichnites eremita to be made
commercially available. We've held it for three years pending the
visit the Cambrian
Shadows Theme Park.
Hagadorn, J. W., and Seilacher, A., Hermits 500 million years ago?:
Geology 37(4), 295-298 (2009).