Sometime during the Cretaceous period, 99 million years ago, a prehistoric hell ant trapped a tasty treat – a relative of the cockroach – in its scythe-like jaw and protruding horn.
It’s still there. The act was captured in tree resin and later unearthed in amber in what is now Myanmar. The unusual find shows how the insect, one of several prehistoric species known as hell ants, used its unique headgear.
“Fossilized behavior is exceedingly rare, predation (the act of predator attacking prey) especially so,” said Phillip Barden, assistant professor at the New Jersey Institute of Technology department of biological sciences and lead author of the research, which published Thursday in the journal Current Biology.
“As paleontologists, we speculate about the function of ancient adaptations using available evidence, but to see an extinct predator caught in the act of capturing its prey is invaluable,” he said in a news statement.
The fossil was visible confirmation of how the hell ant mouth parts worked, Barden said. These ancient arthropods snapped their scythe-like jaw bones in a vertical motion to pin prey against their horn-like appendages.
“The only way for prey to be captured in such an arrangement is for the ant mouthparts to move up and downward in a direction unlike that of all living ants and nearly all insects.”
“Since the first hell ant was unearthed about a hundred years ago, it’s been a mystery as to why these extinct animals are so distinct from the ants we have today,” Barden added.
Modern ants uniformly feature mouth parts that grasp by moving together laterally, or side to side.
“Hell ants have two features found in no living species: highly specialized scythe-like mandibles and a wide diversity of horns that are present on what is essentially the forehead,” Barden told CNN in an email.
“One reason these fossils are compelling is that, today, we have about 15,000 known species of ants with all kinds of adaptations, from agricultural leaf-cutter ants with scissor-like mouthparts to army ants specialized as nomadic predatory raiders.”
The specimen, less than an inch wide, is the latest to emerge from northern Myanmar’s rich amber deposits.
While amber fossils have been some of paleontology’s most exciting finds in recent years, ethical concerns about the provenance of amber from the region have emerged.
The authors of this study said the amber specimen was found prior to the Myanmar military taking control of some amber mining areas in 2017 and said the fossil was not involved in armed conflict or ethnic strife.