Parioscorpio venator

Parioscorpio is an extinct genus of arthropod containing the species P. venator known from the Silurian-aged Waukesha Biota of the Brandon Bridge Formation near Waukesha, Wisconsin. This animal has gone through a confusing taxonomic history, being called an arachnid, crustacean, and an artiopodan arthropod at various points. This animal is one of the more famous fossil finds from Wisconsin, due to the media coverage it received based on its original description in 2020 as a basal scorpion.

==Taxonomy== The fossils were originally discovered in 1985, tentatively identified as a branchiopod or remipede crustacean but were neglected for decades. In 2016, some of the fossils now assigned to Parioscorpio were given the name Latromirus and were assigned to an extinct group of early Paleozoic arthropods known as cheloniellids in a Ph.D dissertation, but the name was never published in a peer-reviewed journal and is therefore not valid in accordance with the International Code of Zoological Nomenclature. The fossils known as “Latromirus” were also mistakenly named “Xus yus” in a preprint of a separate paper. Upon initial publication in 2020, Parioscorpio was considered the world's oldest and most primitive known scorpion, older than Dolichophonus from Scotland by several million years. In 2021, the fossils were reanalysed, and Parioscorpio was found not to be a scorpion, but an arthropod of uncertain placement, outside of Mandibulata, Chelicerata and all other groups of extinct arthropods (e.g. Megacheira, Fuxianhuiida, Artiopoda and so on).