Hi ,
You can retarget significantly different skeletons by following the steps in our documentation: [][1]
Be advised, however, this is not an automatic process. You will first have to select a humanoid rig to assign both skeletons to, then you will have to manually align Bones on the Skeletons that are similar in location to the Bones on the Rig. The main bones need to be aligned (upper arm to upper arm, for example) but smaller bones can simply be ignored (Like a hand with 4 fingers vs a hand with only 3 fingers.)
*Your animation will only be distorted if you accidentally retarget the upper arm of one to the lower arm of the other because the animation will be playing for the wrong part of the body.
[1]: