Working here at The Lake, nestled within the Cromhall Quarry, we’re constantly reminded that we’re standing on a treasure trove of prehistoric secrets. Recently, another incredible discovery has been added to that list: a brand-new species of Triassic reptile.

After more than 200 million years buried in the ground, Threordatoth chasmatos has been revealed. This little lizard-like creature was one of the last survivors of the procolophonids, a group that once roamed widely during the Triassic period.

Cromhall Quarry is renowned as a rich source of Triassic wildlife. Gliding reptiles, dinosaur relatives and even one of the earliest known lizards have all been found at the site over the past few decades. It’s truly remarkable to think these animals were once active right here, where we now swim and dive at The Lake.

Dr. Luke Meade, Research Fellow in Palaeobiology at University of Birmingham and lead author of the research detailing these fossils, says the reptile likely resembled modern horned lizards.

“Based on its relatives, Threordatoth would have been a small reptile with bony spikes on its head and potentially some bony armour on its body,” Dr. Meade explained.

“I like to imagine them scampering around the sinkholes and fissures of southwest England in the Late Triassic, looking for plants and bugs to eat while avoiding the early relatives of dinosaurs.”  

While incomplete jaw fragments have only been found so far, these fossils are crucial for understanding the enigmatic procolophonids.

“These animals were generally quite small, so their bones are vulnerable to being damaged or destroyed before the process of fossilisation,” said Dr. Marc Jones, Curator of Fossil Reptiles at the Natural History Museum in London.

“Generally, this means that we only have the teeth and jaws of these animals and as a result, there’s still a lot we don’t know about them. By continuing to investigate sites like Cromhall, we can hopefully answer some of our outstanding questions.”

A Glimpse into Procolophonids

For those unfamiliar, procolophonids were an important part of Earth’s ecosystems from the end of the Permian period into the Triassic around 252 million years ago. They might look like lizards but they’re not closely related; it’s a case of convergent evolution, the process where unrelated organisms independently evolve similar traits or features.

Many of these fossils, including Threordatoth, have been found in fissure fills around the quarry – ancient cracks that trapped the remains of these small creatures.

Unique Jaw and Teeth

What truly sets Threordatoth apart is its unique jaw and teeth. Dr. Jones described the unusual jaw structure:

“The front of the jaw, for example, isn’t fused together, and there’s no obvious site where they would connect together. Instead, we think that the two halves of the jaw were probably connected by ligaments.

“If this was the case, the jaw would have been somewhat flexible. It may have aided tooth-on-tooth contact during chewing and provided some shock-absorption potential, preventing forces being transferred between the two sides of the jaw.”  

“The teeth of procolophonids are complicated, with enamel that is relatively thick compared to other reptiles. It’s been suggested that the complexity of these teeth allowed them to process a range of foods including plants and insects.” 

Dr. Meade added, “As time passes, we see that most procolophonids develop teeth with two points and reduce their tooth count. It’s thought this might have allowed these animals to eat tougher diets, perhaps as they became more herbivorous.”

“Threordatoth took the tooth reduction trend further than any other procolophonid in the Late Triassic. It has just four teeth on either side of its jaw and each of those teeth has three points, hence the name Threordatoth, which translates as ‘three-pointed teeth’ in Old English.

Using the Past to Inform the Future

The Late Triassic was a period of intense environmental upheaval, as the supercontinent Pangaea began to break apart. The unique dental features of Threordatoth suggest it might have occupied a specialised ecological role within this shifting climate, potentially feeding on plants, insects, or other small prey that demanded specific oral processing.

Dr. Marc Jones said: “Threordatoth lived at a time when solar irradiance was significantly lower than today but atmospheric CO₂ was significantly greater. Overall, it was hotter, average global sea level was higher, and there were extreme rainfall events. Therefore, Threordatoth chasmatos and the community in which it lived could potentially provide perspectives for today’s threatened ecosystems and the planetary emergency we face.”

More Discoveries on the Horizon?

The only other procolophonid with teeth anything like this is another similar species unearthed at Cromhall called Hwiccewyrm. As investigations continue, the team are hopeful that additional fossils will help to reveal more about the Triassic’s fauna:

“A range of species from all sorts of different groups have already been found at Cromhall,” Dr. Meade concluded.

“However, there’s a lot more material that’s yet to be investigated which could contain many other species. Sifting through this material for tiny fossils is time consuming, but it could help to explain more about the diversity of animals like the procolophonids.”

We’re excited to see what other secrets Cromhall will reveal in the future.