Link to the euthycarcinoid page for a more detailed description of this exceedlingly rare fossil.

Despite a more than a decade since ichnofossils and jelly fish fossils were discovered in the Krukowski quarry, a single layer has yielded these body fossils of the conjectured track maker of Protichnites, Diplichnites and other ichnogenera. Interestingly, besides the Krukowski quarry, only one other site in Argentina in the fossil record has both euthycarcinoid fossils together with Protichnites-like trackways. Since the Krukowski quarry is probably an older Cambrian assemblage, these may be the earliest arthropod fossils in the fossil record that are associated with land-based footprints.

Some dozen specimens have been removed with a large holotype specimen reserved for scientific study that has some 175, small euthycarcinoids measuring about one to two inches; a few of these exhibit fine leg and tail details. Eight specimens, including this one, contain about 8 to 12 small arthropods in an apparent death assemblage. Another three specimens are large, single animals that are about five inches in length. The smaller animals may be hatchlings, few of which survived to larger size. The larger animals may be yearlings or older, for example. Given that many tracks from the Krukowski quarry have a width of two or more inches, most trackway inchnofossils in the quarry may have been made by older, larger euthycarcinoids. Assuming no other arthropod-containing layer is discovered in the Krukowski quarry, this fossil may be one of the only few that will ever become commercially available.

The Cambrian euthycarcinoid assemblage offered here is a section of the singular level where these fossils have been found, and contains the hypo-relief (the underside of the bedding plane, with no counterpart) carapace compression imprint of 13 animals. They present in deep relief with little detail.

Note that these fossils of a soft-bodied arthropod occur in course sandstone formed from a turbulent Cambrian shoreline. Such an environment yields body fossils as opposed, for example, to the soft-bodied preservation possible in Laggerstaten formations such as Chengjiang or the Burgess shale where animals were buried in fine marine sediment providing anoxious conditions low or depleted in oxygen.