Habelia optata – The Cambrian arthropod with a ‘Jacknife’ head

Until recently, paleontologist have had difficulty deciding where the Habeliida taxa belonged on the tree of life. A recent re-description of the arthropod habelia optata places the Habeliida next to the Chelicerata. Horseshoe crabs, sea spiders, scorpions and spiders are all Chelicerates.