Deaf Ancestors?

We may have come from deaf ancestors. That's the implication of a new study out of Denmark. A University of Southern Denmark research group studied the lungfish. These are the closest living relatives to the tetrapods, which are associated with the water-to-land transition. It turns out they are not sensitive to sound pressure, but sensitive to vibrations. Scientists say the tympanic ear for hearing didn't develop until the Triassic Age, more than 100 million years after the origin of tetrapods. Details are in the online journal Biology Letters.