Photo credit: Pixabay as posted in Discovery News
New research shows that pearlfish (Onuxodon fowleri) not only reside in black-lip pearl oyster shells, they also use the shells to amplify sounds created by vibrating their swimbladders. According to lead study author Dr. Loic Kéver, "amplification probably improves the efficiency of communication by increasing the propagation distance of the sounds."
Following high resolution CT scans, Dr. Kéver noted, "the rostral [front] end of the swimbladder forms a mineralised structure – called the rocker bone – on which insert the primary sonic muscles." Vertebrae close to the swim bladder are additionally modified suggesting that the rocker bone acts as an anchor for the sonic muscles that are responsible for vibrating the swim bladder.
Sources:
Kéver L, Colleye O, Lugli M, Lecchini D, Lerouvreur F, Herrel A and Parmentier E. (2014) Sound production in Onuxodon fowleri (Carapidae) and its amplification by the host shell. J. Exp. Biol. 217, 4283-4294.