Straight-jawed lacewing larvae (Neuroptera) from Lower Cretaceous Spanish amber, with an account on the known amber diversity of neuropterid immatures.

Abstract

Three larval neuropterans (Insecta: Neuropterida) with straight mandibulomaxillary stylets are described from Lower Cretaceous (late Albian, ~105 Ma) Spanish amber: a third-instar beaded lacewing (Berothidae) from the Peñacerrada I locality (Burgos, Spain), and two specimens from the San Just locality (Teruel, Spain), i.e., a tentative first-instar beaded lacewing and a remarkable specimen considered a berothid-like mantispoid or dilaroid (instar unknown) displaying a combination of potentially plesiomorphic characters and some unique features. These morphotypes are among the oldest straight-jawed neuropteran larvae described. According to the morphology of the specimens and the taphonomy of the amber pieces where they are embedded, the described forms are regarded as active predators of small soft-bodied arthropods, probably living among bark or other vegetation of the resin-producing forest although they could have frequented the soil. An account of the diversity of larval Neuropterida described and/or figured from amber localities worldwide is provided, including reassessments of some specimens. The gathering diversity of fossil immature neuropterans, like that of their adult counterparts, already leans towards reflecting a greater diversity and disparity of the group in deep time ‒particularly during the Cretaceous‒ than in modern days, and it is worthy of increased research efforts due to the evolutionary and palaeobiological potential that it holds.