| Named By: | Charles Doolittle Walcott in 1919 | 
| Time Period: | Chengjiang-Burgess Shale | 
| Location: | Canada - Burgess Shale. China, Chengjiang. USA, Utah | 
| Size: | Up to 3 centimetres across | 
| Diet: | unavailable | 
| Fossil(s): | At least 23 individuals | 
| Classification: | | Animalia | Hemichordata | Pterobranchia | | 
Yuknessia is an early pterobranch, known from the Burgess shale, the Chengjiang 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.