Shonisaurus sikanniensis (Nicholls and Manabe 2004, renamed by Sander et al. 2011) was a giant Late Triassic ichthyosaur at 18-21 meters (69 feet). It did not preserve a rostrum, but no teeth were found with what remained of the giant jaws. Among tested taxa S. sikanniensis nested with Cymbospondylus not the holotype of Shastasaurus pacificus. Flippers were not preserved but the girdles that were preserved suggest small flippers. Sander et al. 2011 considered this specimen conspecific with Shastasaurus, but the two are not related.

Nicholls EL, Manabe M 2004. Giant ichthyosaurs of the Triassic - a new species of Shonisaurus from the Pardonet Formation (Norian: Late Triassic) of British Columbia. Journal of Vertebrate Paleontology 24 (3): 838–849.

Sander PM, Chen X-C, Cheng L and Wang X-F 2011. Short-snouted toothless ichthyosaur from China suggests Late Triassic diversification of suction feeding ichthyosaurs. PlosOne DOI: 10.1371/journal.pone.0019480