Great trilobite Harry. I actually talked to Dave Rudkin last week at a club meeting. I had set up a display of Ontario fossils, including my Isotelus "mafritzae". Dr. Rudkin explained that, while that name is commonly used for these variations of Isotelus, they has never been formally described. It was intended to be named I.mafritzae, after Dr. Madeleine A. Fritz, but basically they haven't gotten around to it yet, so technically, as he put it, it's still an undescribed species.
Isotelus harrypristisi
Isotelus harrypristisi