LAUSR

Significance Extinct animals usually had complex acoustic behavior, but fossils reveal little of these details. Here, we report the earliest insect ears and sound-producing system found in Mesozoic katydids. These katydids evolved unexpectedly high acoustic diversity. Our analysis shows that katydids are the earliest known animals to have evolved complex acoustic communication, acoustic niche partitioning, and high-frequency musical calls. Our results not only suggest that acoustic communication might have been an important driver for the early radiation of katydids but also support the hypothesis of the acoustic coevolution of mammals and katydids. These findings unveil acoustic behavioral complexity and evolutionary adaption amongst Mesozoic katydids and contribute to understanding the evolution of Mesozoic soundscape thus far mostly inaccessible from the paleontological record.