The first corydalid larva (Megaloptera: Corydalidae) with gut-contents from the Early Cretaceous Jehol biota of northeastern China

Abstract The fossil record of the family Corydalidae (Megaloptera) is rare with only six reported species and several undescribed larvae from the Middle Jurassic to Eocene. Little is known about the food habits and digestive system of ancient insects. We report the first corydalid larva preserved with gut contents from the Lower Cretaceous Yixian Formation of northeast China, examining the contents using a scanning electron microscope with energy dispersive X-ray analysis. The results show that the main component of the gut contents is quartz gastroliths ('stomach stones'), providing the first fossil evidence of a gastric mill promoting digestion in a megalopteran larva, extending the record of this behaviour to the Early Cretaceous.