mazonensis would be most related to the octopods based on its lack of a shell. However, later studies found the placement within Octopoda to be dubious, due to the fossils poor preservation, and the fact that other fossils have now shown true octopi to have first arose in the Jurassic. In 2021, it is considered that is even unlikely to be cephalopod or mollusk. Lack of a shell is a highly unlikely combination in a Carboniferous cephalopod. In addition, its appendages lack hooks, suckers, cirri, an arm web, and the characteristic 8/10 arm count. There is neither a beak, unambiguous ink sac, nor radula. The bulbous body outline and presence of appendages more likely to show the affinity as a cnidarian, a phylum of invertebrate animals including jellyfish and sea anemones. Mazon Creek Located in what is currently northern Illinois, the Mazon Creek preserved the Pohlsepia mazonensis fossil extraordinarily. The Pohlsepia mazonensis fossil was found specifically in the Francis Creek Shale Member and like most fossils found in Mazon Creek, is preserved as carbon film. The Francis Creek Shale Member of the Carbon Formation has a diverse array of preserved plants and animals. These organisms were immediately buried due to bursts of water and their remains were protected before most decomposition could start. In storm surges organisms would be submerged in sediments, creating an environment where their fossils were extremely well protected. Field Museum of Natural History The Pohlsepia mazonensis fossil is currently located at the Field Museum of Natural History in Chicago, Illinois. Located eighty miles from the fossil's discovery, the museum is one of the largest natural history museums in the world. It also houses similar fossils in the Mazon Creek Fossil Invertebrates Exhibit. These fossils include spoon worms, ribbon worms, bristle worms, millipedes, and cockroaches. References External links The Octopus News Magazine Online: Fossil Octopuses Fossil taxa described in 2000 Controversial taxa Species known from a single specimen