Evolution of our mammalian ancestor's ear bone

It has long been believed that the hearing bone called stapes, one of the smallest bones in ancestor of mammals, shows no differences between species.

Evolution of the mammalian middle ear: a historical review - Maier - 2016 - Journal of Anatomy - Wiley Online Library

6 Evolution of the inner ear bony housing in mammaliaforms: (A)

New Jurassic mammaliaform sheds light on early evolution of mammal-like hyoid bones

Quadroarticular vs Dentary-Squamosal jaw

Comparison of the ear region of therapsids and modern mammals. A.

In the news–whale ancestors, and more ear bones

Transient role of the middle ear as a lower jaw support across mammals

Chinese and American paleontologists discover

Embryonic evidence uncovers convergent origins of laryngeal echolocation in bats - ScienceDirect

Evolution of the Middle and Inner Ears of Mammaliaforms: The Approach to Mammals