Yuknessia is an early pterobranch, known from the Burgess Shale and the Wheeler Shale. Long, unbranched fronds emerge from a central holdfast-like body covered in small conical plates. 23 specimens of Yuknessia are known from the Greater Phyllopod bed, where they comprise < 0.1% of the community. The genus contains two species: the type species Y. simplex and Y. stephenensis. It was originally interpreted as a green alga, and has since been reinterpreted it as a colonial pterobranch.
References
External links "Yuknessia simplex". Burgess Shale Fossil Gallery. Virtual Museum of Canada. 2011. (Burgess Shale species 136)