Yohoia's a tiny, extinct animal from the Cambrian period that's been found as fossils in the Burgess Shale formation of British Columbia, Canada. It's been placed among the arachnomorphs, a group of arthropods that includes the chelicerates and trilobites. Their sizes range from 7 to 23 mm. Specimens of Yohoia have a head shield which's followed by 13 trunk tergites, or plates. On both sides, the bottom side of the first 10 of these ended in backward-pointing, triangular points or projections.… (More on Yohoia)