Scientist calls fossilized assassin bug private parts 'a rare treat'

A stunningly well-preserved 50-million-year-old fossil is giving insights into insect history.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
2 min read

Found in Colorado, this fossil is a species now called Aphelicophontes danjuddi. A small beetle also appears with the larger assassin bug.

Daniel Swanson/Palaeontological Association

Perhaps the phrase should be "snug as a bug in a rock."

University of Illinois entomology graduate student Daniel Swanson was able to see the intimate details of an assassin bug's genitalia in a 50-million-year-old fossil. The genital capsule is as small as a grain of rice, but it's revealed its secrets after all this time.

"To see these fine structures in the internal genitalia is a rare treat," Swanson said in a University of Illinois statement on Tuesday. "Normally, we only get this level of detail in species that are living today."  

There's a lot scientists can learn from bug private parts, which can help determine if an insect is a previously unknown species. This extinct specimen represent a new species of the predatory insect, and the find helps to extend the history of banded assassin bugs by 25 million years.

"There are about 7,000 species of assassin bug described, but only about 50 fossils of these bugs are known," Swanson said. "This just speaks to the improbability of even having a fossil, let alone one of this age, that offers this much information."  

The fossilized bug had quite a journey. It was found in 2006 in modern-day Colorado in an area called the Green River Formation. The fossil split cleanly in half and was sold by a dealer to two different collectors. The researchers hunted the two pieces down to conduct the study of the insect. 

One of the collectors, Dan Judd, donated his side of the bug to the Illinois Natural History Survey, which worked on the study, and received quite a tribute in return. The research team named the new species "Aphelicophontes danjuddi."