Making bone animations in Unity

Hey folks,

I am currently searching for a way to implement bone animations in Unity. I have 2D sprites of a character, of which I have all his limbs as separate textures.

Now my question is: What would be the best way to coordinate and animate this textures?

Zombieville appararently used a 3D modelling program to coordinate and animate the limbs acordingly. But this way I don't see how you can animate the limbs as normal sprite animations.

Can anybody help me on this? Maybe linking to projects or tutorials.

It is greatly appreciated Thank you