This week on Fossil Friday, I’m sharing one of my favorite specimens from the University of Iowa fossil repository. I found this fossil particularly cool because I love organic patterns. You see so many repeating motifs across time, space, and species. What do you think this pattern came from? I’ve seen shapes like this when doing microscopy on mammalian cells, but I promise you, this fossil has very little to do with that. The specimen is from the Pennsylvanian subperiod, and was collected in Pella, Iowa. Be the first to identify it in the comments, and win bragging rights for the week!