From setae to scales: Burmese amber fossils reveal the Early Cretaceous innovation of body coverings in scaly crickets

Abstract Scales have evolved independently in multiple insect orders, contributing to colour diversity through both pigmentary and structural mechanisms. Within Orthoptera, the subfamily Mogoplistinae (Grylloidea: Mogoplistidae) represents the sole lineage bearing specialized scales, yet the evolutionary origins of this unique body covering remain poorly understood. Here, we report four new species critical to resolving this question: Protomogoplistes ciliatus sp. nov., Crinitipes calvus gen. et sp. nov., Birmanimogoplistes acutifolius gen. et sp. nov. and Angustisquama bicolorata gen. et sp. nov. We demonstrate that Mogoplistinae scales are derived from modified setae, and our results reveal that scale evolution in Mogoplistidae followed an ‘innovation-first, radiation-later’ trajectory, with this key innovation emerging by the mid-Cretaceous. The development of scales probably served as a pivotal driver, facilitating Mogoplistinae’s subsequent ecological diversification.