Reptilian ear 3D morphometric data

Reptiles, including birds, exhibit a range of behaviorally significant adaptations reflected in changes to the structure of the inner ear. These adaptations include capacity for flight and sensitivity to high-frequency sound. We used 3D morphometric analyses of a large sample of extant and extinct reptiles to investigate inner-ear correlates of locomotor ability and hearing acuity. Statistical analyses revealed three vestibular morphotypes, best explained by locomotor categories: quadrupeds, bipeds and simple fliers (including bipedal non-avialan dinosaurs), and high-maneuverability fliers. Troodontids fall with Archaeopteryx among extant low-maneuverability fliers. Analyses of cochlear shape revealed a single instance of elongation, on the stem of Archosauria. We suggest that this transformation coincided with the origin of high-pitched juvenile location, alarm, and hatching-synchronization calls, and adult responses to them.包括鸟类在内的爬行动物，展现出一系列具有重要行为意义的适应性特征，这些特征体现在内耳结构的变化之中。这些适应性特征包括飞行能力以及对高频声音的感知灵敏度。本研究针对大量现生与灭绝爬行动物样本开展三维形态计量分析（3D morphometric analyses），探究内耳结构与运动能力、听觉敏锐度之间的关联。统计分析结果表明存在三类前庭形态类型（vestibular morphotypes），其差异可通过运动功能类别得到最优解释：四足动物、两足动物与简单飞行类（包括两足非鸟翼类恐龙（non-avialan dinosaurs）），以及高机动性飞行类。伤齿龙类（Troodontids）与始祖鸟（Archaeopteryx）一同被归入现存低机动性飞行类群。对耳蜗形态的分析显示，仅在主龙类（Archosauria）干群阶段出现过一次耳蜗延长的演化事件。我们推测，该形态转变与幼体用于定位、警戒以及同步孵化的高频叫声，以及成体对此类叫声的响应行为的起源时间相吻合。