Dr. Qvarnstrom initially thought the insects must have climbed aboard following defecation. But the researchers saw many different stages of chewed-up-ness, so to speak, from almost fully preserved bodies down to disembodied heads, wings and other parts, many from the same kind of boat-like, millimeter-and-a-half-long beetle.
The researchers determined that the new species and genus, Triamyxa coprolithica, belongs to an extinct and previously unidentified family in a lineage of small beetles, Myxophaga, that today tend to live around algal mats. According to the authors, this is the first insect species described in the fossilized feces of a vertebrate animal.
As for how some beetles made it through the animal’s gut without much damage, Dr. Qvarnstrom thinks there are a few possibilities. The beetles were tiny, and might have been accidentally sucked up en masse while congregating on a piece of algae eaten by a Silesaurus opolensis; they also seem to have been well-defended by their exoskeleton, like modern beetles. The ones who weren’t chewed up still probably died quickly, Dr. Qvarnstrom said. “They didn’t have to suffocate in the poop.”
Beetles are probably the most diverse group of organisms on the planet, and learning more about their early evolution could help researchers understand why that is, said Martin Fikacek, a co-author and entomologist at National Sun Yat-sen University in Taiwan.
The Triassic Period, when this coprolite was produced, is “kind of a black hole when it comes to our understanding of the insect fossil record,” Dr. Heads said. “A beetle of the Triassic age is really a significant discovery.”
Learning more about the diets of these close dinosaur relatives, Dr. Qvarnstrom said, might also help researchers better understand how dinosaurs eventually became so ecologically dominant.
“If we want to know more about the past,” he said, “I think it’s fairly important to get all the pieces of the puzzle.”