Beyond the limits: identifying the high-frequency detectors in the anuran ear

Despite the predominance of low-frequency hearing in anuran amphibians, a few frog species have evolved high-frequency communication within certain environmental contexts. Huia cavitympanum is the most remarkable anuran with regard to upper frequency limits; it is the first frog species known to emit exclusively ultrasonic signals. Characteristics of the Distortion Product Otoacoustic Emissions from the amphibian papilla and the basilar papilla were analysed to gain insight into the structures responsible for high-frequency/ultrasound sensitivity. Our results confirm the matching of vocalization spectra and inner ear tuning in this species. Compared to most anurans, H. cavitympanum has a hyperextended hearing range spanning from audible to ultrasonic frequencies, far above the previously established “spectral limits” for the amphibian ear. The exceptional high-frequency sensitivity in the inner ear of H. cavitympanum illustrates the remarkable plasticity of the auditory system and the e...尽管无尾两栖类（anuran）的听觉以低频感知为主导，但少数蛙类已在特定环境背景下演化出高频通讯能力。阔口泛树蛙（Huia cavitympanum）是目前已知在高频上限特性上最具代表性的无尾两栖类，也是首个被证实仅能发出超声信号的蛙类。研究团队针对两栖乳头（amphibian papilla）与基底乳头（basilar papilla）的畸变产物耳声发射（Distortion Product Otoacoustic Emissions）特征开展分析，以期解析该物种对高频/超声敏感的听觉结构基础。研究结果证实，该物种的发声频谱与内耳调谐特性高度匹配。与多数无尾两栖类相比，阔口泛树蛙拥有超宽的听觉范围，覆盖从可听声到超声的全频段，远超此前学界确立的两栖类听觉频谱极限。阔口泛树蛙内耳优异的高频感知能力，直观展现了听觉系统极强的可塑性与……