Elrathia marjumi Trilobite from Utah

Description: Presented is a well-preserved specimen of Elrathia marjumi. The preservation is superb and the prep work first rate. The specimen sits comfortably on a large and solid plate.

The species derives its name from the formation directly on top of the layer containing the common Elrathia kingii, and may be a direct descendant.?The differences are small. The main difference is two short stubby spines (compared with E. kingii) on the pygidium, just below the last thoracic segment. But even in the closeup it is hard to see. This species is found higher in the Cambrian strata, than E. kingii, and the marjumi are found in matrix that is much harder than that of kingi, making preparation much more difficult.