Yuknessia is an early pterobranch, known from the Burgess shale,[1] the Chengjiang and the Wheeler shale.[2] Long, unbranched fronds emerge from a central holdfast-like body covered in small conical plates.[1] 23 specimens of Yuknessia are known from the Greater Phyllopod bed, where they comprise < 0.1% of the community.[3] The genus contains two species: the type species Y. simplex and Y. stephenensis.[2] It was originally interpreted as a green alga, and has since been reinterpreted it as a colonial pterobranch.[2][4][5]