Figure 2.

ABR-derived audiogram of the African lungfish (n = 5). The two curves are measurements of mean masked ABR thresholds to head vibration (squares) and to underwater sound (circles). (a) Thresholds measured as particle acceleration. (b) The thresholds plotted are equivalent free-field sound pressures in dB RMS re 1 µPa, i.e. the free-field sound pressure corresponding to the vibration thresholds as derived with ABR. Note that these evoked potential thresholds are probably at least 10–30 dB above psychophysical thresholds.