Pikaia gracilens is an extinct, primitive chordate animal known from the Middle Cambrian Burgess Shale of British Columbia. Sixteen specimens are known from the Greater Phyllopod bed, where they comprised 0.03% of the community. It resembled the lancelet and perhaps swam much like an eel. Its exact phylogenetic position is unclear. Proposed affinities include cephalochordata, craniata, or a stem-chordate not closely related to any extant lineage.