The fish's hyomandibula bone in the hyoid region behind the gills diminished in size and became the stapes of the amphibian ear, an adaptation necessary for hearing on dry land.
ðə fˈɪʃᵻz hˌaɪəmɐndˈɪbjʊlə bˈoʊn ɪnðə hˈaɪɔɪd ɹˈiːdʒən bᵻhˌaɪnd ðə ɡˈɪlz dᵻmˈɪnɪʃt ɪn sˈaɪz ænd bɪkˌeɪm ðə stˈeɪps ʌvðɪ æmfˈɪbiən ˈɪɹ, ɐn ˌædæptˈeɪʃən nˈɛsᵻsɚɹi fɔːɹ hˈɪɹɪŋ ˌɔn dɹˈaɪ lˈænd.