Anomalocaris ("unlike other shrimp", or "abnormal shrimp") is an extinct genus of radiadont, an order of early-diverging stem-group arthropods. It is best known from the type species A. canadensis, found in the Stephen Formation (particularly the Burgess Shale) of British Columbia, Canada. Other closely related fossils have been found in the older Emu Bay Shale of Australia and possibly elsewhere. Originally, several fossilized parts discovered separately (the mouth, frontal appendages)