A team of paleontologists recently excavated something extraordinary in UtahOpens in a new tab: a 300-million-year-old fossil of some as-yet-unidentified species of reptile. Or amphibian. It’s unclear. Regardless, the paleontologists say the fossil stands as a “once in a lifetime kind of skeleton” that likely represents a new species of slithery creature.

Smithsonian MagazineOpens in a new tab reported on the new, ancient fossil from Utah, which likely comes from a novel tetrapod species. Tetrapods, as their moniker implies, are four-limbed animals. They are often ones from extant, as well as extinct, amphibian and reptile species. (Examples of tetrapods include everything from toads to aquatic snakes.)
Paleontologists from the Petrified Forest National Park in Arizona, along with researchers from the Natural History Museum of Utah and the University of Southern California, excavated the fossil from a slickrock wash in the Canyonlands National ParkOpens in a new tab. Apparently, the tetrapod’s fossil is quite well intact. The creature’s rock-mineral skull, backbone, forelimbs, hind limbs, and pelvic girdle are all present.
Adam Huttenlocker, a biologist at the University of Southern California, sharedOpens in a new tab that “this fossil appears to be an early amniote, which is a land-living vertebrate that lays eggs.” He also went on to sayOpens in a new tab, “Because the fossil is so complete, it will help to shed light on the controversial evolutionary relationships of early amniotes, including reptiles and the extinct ancestors of mammals (synapsids).” The fact this is the first amniote fossil paleontologists have recovered from the area from this time period makes the team confident it’s a new species. Though it is important to note, they are not certain yet if it is.
The paleontologists also still need to narrow down when precisely this creature roamed Earth. Although they already have it pegged at somewhere between 290 and 310 million years ago. The timeframe likely places this tetrapod in the Permian geologic period, which began around 300 million years ago. The Permian spanned up to the Triassic—which led up to the Jurassic PeriodOpens in a new tab—meaning the reptile/amphibian predated the dinosaurs.

As for some kind of record for the oldest animal fossil? Three hundred million years old doesn’t even make the traces of tetrapod a top contender. In Nevada, for example, paleontologists have found a 550-million-year-old digestive tract. And if further data confirms it, we may even have fossils from 860 million years agoOpens in a new tab.