It is believed that the coelacanths and lungfish (lobed fin fishes) represent a crucial link between other fishes and tetrapods. what is the major feature in these fish in support of this hypothesis?

It is believed that the coelacanths and lungfish (lobed fin fishes) represent a crucial link between other fishes and tetrapods. The major feature to support the hypothesis is : Their fins have skeletal and muscular structures similar to amphibian limbs.