RARE Cambrian Echinoderm Fossils Association

Description: Coming from the Cambrian Wheeler Formation deposits of Millard County, Utah this is an association plaque of a member of the Ctenocystoidea, a small class of bilaterally-symmetrical stem echinoderms and the eocrinoid Gogia.. The ismall examples are Ctenocystis, a flattened rectangular animal covered with tesselated plates. It derives its named from the ctenoid (comb-like) plates that circled the oral opening. One researcher has postulated that these plates were used to drag the animal along the seafloor. Ctenocystis is found in the same quarry as Gogia, but only occupies 3 thin (5 mm) layers, offering another example of the stem-group echinoderms to be found in the Middle Cambrian of Utah. The other examples are Gogia spiralis, a member of the Class Eocrinoidea. Eocrinoids (“dawn crinoids”), were among the earliest groups of Echinoderms. They had a vase-shaped body (calyx), covered by plates that were symmetrical and had a bifurcated brachiole, a slender arm-like structure for food-gathering that closely resembled those in cystoids. The early Eocrinoids were attached to the bottom by a thick holdfast. Later members had an elongated stalk much like the true crinoids which evolved later. Once Gogia matured past the 4-armed stage (the species derives its name from the spiraled arms), they added arms in such a way as to have an odd-numbered total.