Evolution and mandibular sexual dimorphism in mid‐Cretaceous scorpionflies (Insecta: Mecoptera: Meropeidae)

Abstract

Based on several earwigfly specimens with well‐preserved mouthparts of Meropeidae from mid‐Cretaceous Burmese amber, a detailed, initial analysis was conducted of the structure of Mesozoic meropeids. Compared to the singularly flattened mandible of modern meropeids, the new specimens reveal that Mesozoic representatives had two distinct types of mandibles: blade‐shaped and scoop‐shaped. Current fossil evidence indicates that during the Mesozoic Era, Meropeidae displayed sexual dimorphism that was reflected in the structure of their mandibles. This structural difference may indicate that about 99 million years ago, meropeids had a more complex diet than extant confamilial taxa. Phylogenetic results suggest that Torvimerope gen. nov., along with Burmomerope, two extinct genera, form a clade and that are the sister taxon to crown‐group Meropeidae. The new material offers new possibilities for inferring the feeding habits and mating behavior of early Meropeidae.