A new discovery published this week in the Journal of Paleobehavioral Studies suggests that some carnivorous dinosaurs may have been more advanced than originally believed possible. Not technologically speaking of course but in what many paleontologist believe to be an advanced grooming behavior.

The breakthrough, published this week in the Journal of Paleobehavioral Studies, points to the presence of fibrous plant material lodged between the teeth of theropod fossils — material initially dismissed as a quirk of the fossilization process though some believed it could be the preservation of a plaque build up.

An analysis of the fibrous strands revealed a structure consistent with ancient Pseudotextilis lignis, a stringy, bark-like plant thought to have thrived worldwide during the Late Jurassic period. With a texture described as “prehistoric woody celery,” this plant’s tough, sinewy strands has been confirmed to be the common element throughout a remarkable sample size.

Researchers at the University of Pangea’s Department of Paleo-Microbiology conducted a comparative analysis of over 150 carnivorous dinosaur specimens, including Tyrannosaurus rex, Allosaurus, and Velociraptor. In nearly 70% of the jaws, remnants of P. lignis were found wedged between teeth. Notably, these fibers were completely absent in herbivorous dinosaurs.

“We believe these carnivores used strands of P. lignis to remove problematic leftover sinew and bone shards from between their teeth,” explained lead researcher Dr. Helena Mandibula. “Often in patterns that produced only the slightest, repeated wear to the enamel—suggesting deliberate and consistent motion. Not unlike how we use floss.”

Naturally, the community is divided.

Some paleontologists caution that this could simply be a case of environmental contamination—that the fibers were inadvertently consumed along with prey, and not intentionally used. While others are calling this the most exciting behavioral fossil evidence since the discovery since the 2012 study of synchronized nest-building among certain Cretaceous birds.

Regardless of interpretation, the implications are jaw-dropping. If confirmed, this would mark the first discovery of what scientists are calling the first ever flossilization record.