Carboniferous Horseshoe Crab Euproops rotundatus with Preserved Telson

Description: Xiphosura (horseshoe crabs) are related to the extinct Eurypterids, and more distantly to spiders and scorpions. They trace their ancestry back to the Cambrian, and proceed into the modern day as the genus Limulus. This one is most like the more common member of the genus known as Euproops danae found in the Mazon Creek deposits of Illinois which looks much like the splendid fossil offered here. The distinguishing feature of this one is the far more rounded (rotund) aspect. The proximal half of the telson is preserved as well, a feature rarely preserved in the same nodule. Fossil examples such as this one are highly-prized by collectors, and rarely seen for sale. The location from which this very 3-D specimen was collected is currently being landfilled, so the odds of one being found here are slim indeed. See my other offerings for 2 other Xiphosurans of different morphology.