Reversal to air-driven sound production revealed by a molecular phylogeny of tongueless frogs, family Pipidae

BACKGROUND: Evolutionary novelties often appear by conferring completely new functions to pre-
existing structures or by innovating the mechanism through which a particular
function is performed. Sound production plays a central role in the behavior of frogs, which use their calls to delimit territories and attract mates. Therefore, frogs have evolved complex vocal structures capable of producing a wide variety of advertising sounds. It is generally acknowledged that most frogs call by moving an air column from the lungs through the glottis with the remarkable exception of the family
Pipidae, whose members share a highly specialized sound production mechanism
independent of air movement. RESULTS: Here, we performed behavioral observations in the poorly known African pipid genus Pseudhymenochirus and demonstrate that sound production in this aquatic frog is air-driven. However, morphological comparisons revealed an indisputable pipid nature of Pseudhymenochirus larynx. To place t...

背景：进化新性状的出现，通常是通过为预先存在的结构赋予全新功能，或是通过革新执行特定功能的机制来实现的。发声在蛙类行为中占据核心地位，蛙类通过鸣叫划定领地并吸引配偶。因此，蛙类演化出了复杂的发声结构，能够产生种类繁多的求偶鸣叫。普遍认为，大多数蛙类通过将肺部的气流柱经由声门（glottis）排出而发声，但负子蟾科（Pipidae）是显著例外——该科成员拥有一种高度特化、不依赖气流运动的发声机制。

结果：在此，我们对鲜为人知的非洲负子蟾属（Pseudhymenochirus）进行了行为观察，并证明这种水生蛙类的发声是由气流驱动的。然而，形态学比较显示，Pseudhymenochirus的喉部具有无可争议的负子蟾科特征。为了将该...