Paleontologists have found that Brindabellaspis stensioi, a species of long-beaked placoderm fish that lived 400 million years ago (Early Devonian epoch), had a surprisingly compact inner ear and that its closely connected components resembled those of modern jawed vertebrates such as sharks and bony fishes. Most placoderms had less complex inner ear structures, with a large sac, called a vestibule, placed in the center and separating all the other...
