Janjucetus hunderi (Fitzgerald 2006; late Oligocene; est. 3.5m in length) was originally considered the basalmost Mysticeti (baleen whale), but it had large leaf-like teeth, was small and had a relatively small head. Here it nests with Anthracobune, prior to the transformation of limbs in derived desmostylians like Behemotops. The whale-like post-crania (above) imnagined by Fitzgerald is not supported by phylogenetic bracketing.
Janjucetus had a full arcade of very unusual teeth with very deep serrations, perhaps used for cutting vegetation. The skull was more than twice as wide as tall. The orbit was at mid skull, not in the posterior half, as in whales and desmostylians.