Skeleton and Muscular Animal Research

My character is mostly based off a frog but in terms of movement and body structure frog legs won't work for my design. Frogs stand on four legs but they move completely differently to dogs etc. Because my character stands on his back legs (like a human) but occasionally walks on all fours (like a gorilla) I looked into different animal skeleton/muscular structures to redesign his back legs.

This what I will base my characters body on (when it walks on all fours). However I will make adjustments to suit him also walking on his backlegs (his usual way or walking).

An otter is a really good example of how I want my characters legs to be. I will have to make adjustments (such as the spacing between the hip and knee to be longer) but the way the otter sits on his back legs is an ideal form.