Paleontologists have described a new species of assassin fly found preserved in two pieces of 100-million-year-old Burmese amber.
Assassin flies are named for their fierce predation strategy – they ambush and catch their prey in flight. Once caught, the flies puncture the armor-like skeleton of their prey, inject them with digestive fluids and extract the nutrients within.
For more than 100 million years, these creatures have ruled the world of insects as a top predator.
The lineages of these flies were previously only studied in limestone fossils dating back to 112 million years.
“The transparency of these amber fossils gives researchers a new window into the ecology of the Cretaceous period, and sheds light on the evolutionary history of a family of flies that has withstood the test of time for millions of years. The fossils of these ancient flies are so well preserved that you can almost imagine them flying around in our world today,” explained Dr Torsten Dikow from the Smithsonian Institution’s National Museum of Natural History, the first author of the paper published in the American Museum Novitates.
The new species of assassin fly from the Cretaceous period has been named Burmapogon bruckschi.
Dr Dikow and his co-author, Dr David Grimaldi from the American Museum of Natural History, identified it after studying the morphology of a male and female specimen using a microscope.
Distinct features that are not found in modern species of assassin flies include long, flattened antennae, a unique v-shaped eye structure and spiny hind legs.
While contemporary species of assassin flies can reach a length of more than 5 cm, Burmapogon bruckschi was less than 2.5 cm long and had bristles covering its slender, piercing mouthparts.
The female Burmapogon bruckschi contained small spines on its abdomen, leading the paleontologists to hypothesize that these insects are most closely related to other assassin-fly species that use these spines to dig and deposit their eggs in sandy environments.
Since Burmapogon bruckschi likely did not spend much time in an arboreal habitat, it is extremely rare to find them in amber, the fossilized resin of ancient forests. Other fly species depend on forests for their life cycle and are therefore more frequently found encased in amber.
Torsten Dikow and David A. Grimaldi. 2014. Robber Flies in Cretaceous Ambers (Insecta: Diptera: Asilidae). American Museum Novitates 3799: 1-19; doi: 10.1206/3799.1