Thought to have originated around 162 million years ago, jewel wasps now represent one of the most diverse groups of insects on the planet. However, their fossil record only went back 100 million years – until now. A lump of amber has revealed a 130-million-year-old family of jewel wasps, and with it, insight into their early evolution.
Jewel wasps belong to Chalcidoidea, a superfamily of parasitic wasps that attack other insects and lay their eggs within them, using a tubular organ called an ovipositor. During a visit to the Natural History Museum in Paris, researcher Lars Krogmann noticed a strange, amber-encased wasp specimen in which the organ was covered by a long tail-like structure.
Although it had been listed as an entirely different species of wasp, Krogmann and his colleagues soon realized that it was an ancient chalcid – in fact, it turned out to be the oldest known specimen in the world. The chunk of amber was originally found in Lebanon, and the unlucky wasp within it was embedded around 130 million years ago during the Cretaceous period.
It also represents an entirely new family of jewel wasps, which the researchers have dubbed Protoitidae. “The family name is derived from being a ‘proto’ form of the Chalcidoidea,” explained Jonah Ulmer, co-author of the study describing the wasp family, in a statement.
The researchers also discovered and named Cretaxenomerus curvus.
A key feature of the new family is the previously mentioned tail-like structure, extending from the end of the wasp’s abdomen; it’s not seen in any living species today. Given its location near the ovipositor, the researchers suspect that it may have helped with egg-laying, or alternatively moving leaves out of the way whilst searching for unsuspecting hosts.
The distinctive structure also meant that the researchers were able to identify other species belonging to the family within other fossils. “Multiple similar specimens in amber soon became apparent and the family now contains two genera, Protoita and Cretaxenomerus,” said Ulmer. In total, the study examined 15 specimens, all stemming from two outcrops in Lebanon.
The discovery provides a rare look into the early evolution of chalcids, filling in the gaps as to how they became what they are today. The researchers also believe that their study demonstrates there are likely many other families of jewel wasps waiting to be found. As Ulmer put it, “Protoitidae shows that we can keep looking further back in time than we expected and still find new, and old, species.”
The study is published in the Journal of Hymenoptera Research.
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