Cretaceous lacewing larvae with binocular vision demonstrate the convergent evolution of sophisticated simple eyes.

Abstract

Many insects and their relatives are renowned for sophisticated compound eyes, which are also preserved in the fossil record. Yet there are other types of eyes, notably the so-called stemmata of holometabolans, such as beetles, bees, and butterflies. Stemmata are not as effective as compound eyes, except in some predatory larvae. Here we report three lacewing larvae with large forward-directed stemmata from Cretaceous Kachin amber, Myanmar. The stemmata are large relative to those of other fossil lacewing larvae, comparable to the simple eyes of modern larvae capable of image formation. The head is very wide in one larva, representing a new type of morphology as demonstrated by a quantitative comparison of the head and stylets of over 400 fossil and extant lacewing larvae. The arrangement of the exceptionally large stemmata of the larvae reported here provides stereoscopic vision. These new specimens demonstrate the convergent evolution of highly developed simple eyes in at least two additional lineages of lacewings, showcasing the enormous diversity of lacewing larvae in the Cretaceous.