is a fossil for the advanced collector and/or ichnologist and/or
museum. Prior to purchase, please review the Cambrian
Shadows theme park section to gain the background to put the
presentation below in context. Additionally, you can see the ichnofossils
nomenclature chart to learn the technical terms that are used.
is not an ichnofossil. Rather, it is the body fossil(s) of the putative
arthropod track maker of Protichnites and Diplichnites trace fossils
coming from the Krukowski quarry, which exposes the Elk Mound Group
of the Mount Simon sandstone in central Wisconsin. This Cambrian
arthropod with body segmentation and tail has resemblance to the
and aglaspids. The Protichnites
tracks found at the site are possibly the oldest terrestrial footprints
in the fossil record.
is one of limited number of these fossils that will be available.
The remainder of the small layer is currently being used for research.
The amphibious arthropods come from an interstitial desiccation
layer between sandstone bedding planes (see ichnofossil
nomenclature chart), where they are preserved as ventral, hyporelief
desiccation zone was likely created by the ingress of fine sediment,
clay or mud in a trough, in which the creatures became entrapped
and then perished; scratch marks on some specimens attest to the
animals struggling to escape. We can hypothesize that, sandwiched
between sand layers, the chitinous exoskeletons of the arthropods
filled with very fine sand and sediment even as mud and silt leached
away, leaving the sandstone body molds to be preserved for the past
half billion years.
are two two carapaces (numbered in the pictures) with many details
preserved, especially considering the coarseness of the quartzite
Vacarri, N.E., Edgecombe G.D. and Escudero C., Cambrian
origins and affinities of an enigmatic fossil group of arthropods,
Nature 430, 554 - 557 (29 July 2004).