Ancient beetle is first insect ever to be discovered — in fossilized poop!

UPPSALA, Sweden — Scientists have discovered a new ancient beetle species in a most unusual place: fossilized poop. Believed to be about 230 million years old, it’s the first insect ever to be found in fossilized feces. Incredibly, 3D imaging shows its legs, antennae and other body parts are still fully intact.

Several of beetles were found inside the fossilized feces, also known as coprolite. They were swallowed whole by a creature called Silesaurus opolensis, the dinosaurs’ closest ancestor. It had a beak at the tip of its jaws to root in the litter and perhaps peck insects off the ground, somewhat like modern birds.

The prehistoric beetle has been named Triamyxa coprolithica.

Beetle found in dinosaur feces
Triamyxa coprolithica anterior view. (Qvarnström et al.)

“We were absolutely amazed by the abundance and fantastic preservation of the beetles in the coprolite fragment,” says study co-author Dr. Martin Qvarnstrom, of Uppsala University in Sweden, in a statement. “When you modelled them up on the screen, it was like they were looking right at you.”

Coprolites are rich in mineralizing bacteria and calcium, which quickly froze the delicate creatures in time. They were eaten along with plants and other bugs the seven-foot long reptile had feasted upon. It enabled the international team to create a detailed reconstruction of tiny Triamyxa using state of the art scanning techniques.

“In a way, we must really thank Silesaurus, which likely was the animal that helped us accumulate them,” says Qvarnstrom.

The beetle represents a family previously unknown to science, and is the first insect to be described from a coprolite. Fossilized feces, common at paleontological dig sites, might contain a host of hidden treasures for scientists. Triamyxa will certainly rank near the top.

The study, published in Current Biology, offers an alternative to amber. The most ancient insects from the fossilized tree resin are 140 million years old. Coprolites can open a window even further into the past, shedding light on insect evolution and food webs of lost worlds.

Artistic reconstruction of Silesaurus. (Uppsala University)

“We didn’t know how insects looked in the Triassic period and now we have the chance,” notes co-author Dr. Martin Fikacek, of National Sun Yat-sen University in Taiwan. “Maybe, when many more coprolites are analysed, we will find some groups of reptiles produced coprolites that are not really useful, while others have coprolites full of nicely preserved insects that we can study. We simply need to start looking inside coprolites to get at least some idea.”

Beetles are one of the most successful species on Earth. Genetic analyses suggest they have been around for about 327 million years.

Triamyxa was about one millimeter long and lived in semi-aquatic or humid environments. It was a favorite snack of Silesaurus, which roamed what is now Poland. At the time Earth was made up of one huge landmass, a supercontinent known as Pangaea.

“Although Silesaurus appears to have ingested numerous individuals of Triamyxa coprolithica, the beetle was likely too small to have been the only targeted prey,” says Qvarnstrom. “Instead, Triamyxa likely shared its habitat with larger beetles, which are represented by disarticulated remains in the coprolites, and other prey, which never ended up in the coprolites in a recognizable shape. So it seems likely Silesaurus was omnivorous – and part of its diet was comprised of insects.

The coprolite was examined with synchrotron microtomography at the European Synchrotron Radiation Facility (ESRF) in France. It uses high-energy X-ray beams thousands of times stronger than a CT hospital scanner. It makes it possible to visualize internal structures in fossils in three dimensions with great contrast and resolution.

“So if you find an insect in the coprolite, you can scan it using microCT in the same way as we do with amber insects, and you can see all the tiny details of the insect body as we do in amber,” says Fikacek. “In that aspect, our discovery is very promising, it basically tells people: ‘Hey, check more coprolites using microCT, there is a good chance to find insects in it, and if you find it, it can be really nicely preserved.'”

Beetle found in dinosaur feces
The tiny beetle Triamyxa coprolithica is the first-ever insect to be described from fossil feces. (Credit: Qvarnström et al.)

The coprolite contained numerous beetle body parts, most belonging to Triamyxa and some virtually complete.

“I never thought we would be able to find out what the Triassic precursor of the dinosaurs ate for dinner,” says Co-author Dr Grzegorz Niedzwiedzki, also from Uppsala.

Comparison with modern beetles found Triamyxa belonged to the suborder Myxophaga, whose members today live on algae in wetlands.

“There are heaps of things you can study based on fossilized droppings,” adds Qvarnstrom. “But it had been hard to understand what to do with it, hard to recognise what is inside and hard to draw conclusions from it – but now there are tons of data. The ultimate goal is to use the coprolite data to reconstruct ancient food webs and see how they changed across time.”

SWNS writer Mark Waghorn contributed to this report.

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