• Fossils of Pseudoarctolepis have been found only in Utah.

• These ancient creatures had a unique appearance, with a carapace made of two valves sutured down the back, and a long spine extending from each side, like a wing. 

• Pseudoarctolepis has such unique anatomy that it does not fit readily with any other species, but it is often classified with the phyllocarids, a group of small marine crustaceans. 

• Studying fossils of Pseudoarctolepis and other extinct arthropods provides valuable insights into the history and special design of arthropods.

• By comparing their morphology and behaviors with those of living arthropods, scientists can better understand the ecological roles these ancient organisms played and learn more about their amazing diversity.