The first Ripipterygidae (Orthoptera: Caelifera: Tridactyloidea) from mid-Cretaceous Burmese amber

The first mud cricket, Archaicaripipteryx rotunda gen. et sp. nov., is described based on a well-preserved specimen from mid-Cretaceous Burmese amber. It can be definitely assigned to Ripipterygidae based on its uninflated mesotibiae, unsegmented cerci and each ventral valve with a powerful side tooth. However, the morphology of this new mud cricket shows distinguishing characteristics including interocular distance at least the width of the compound eyes, metatarsus at least twice the length of the metatibial spurs, and distinctive subapical denticular process on the metatarsus, providing novel morphological diversity of the Ripipterygidae. Archaicaripipteryx rotunda gen. et sp. nov. is not only the first record of the Ripipterygidae from mid-Cretaceous Burmese amber, but also the oldest fossil record of Ripipterygidae, extending the geological range of this family by approximately 80 million years.