User blog comment:Kogath/Monster Hunter: World Discussion/@comment-5020152-20180612185735/@comment-5158920-20180614114355

Rathalos and Barioth do use the same skeleton.....you can clearly see it in Barioth's non-combat walking animation and it's the same for Tigrex and Narga too. They're using the Flying Wyvern skeleton it's just animated to move differently.

This information has been known for years by the community.