Ancient animal discovered on Cape Breton Island may have been one of the earliest plant-eaters, study suggests

A newly discovered, football-sized creature that can grind its teeth like a fanatical plant eater — before it was actually a thing — may be the first-ever vertebrate herbivore ever found.

Tyrannoptera Heberti About 315 million years ago, at the end of the Carboniferous period, they lived in dense, ferny swamps on Cape Breton Island in Nova Scotia. At the time, known four-legged animals, or tetrapods, ate mostly other animals, including insects, as they had not yet discovered a way to chew and digest leaves and bark.

The new species is the first four-legged animal with the right kind of teeth for a plant-based diet, According to a new study describing. “It kind of reshapes our understanding of how fast this change happened,” said Arjan Mann, lead author of the study. The study published last week in Nature Ecology and Evolution.

tyrannosaur

Tyrannoroter was a “microsaur” – a small, lizard-like creature related to reptiles and mammals that lived before reptiles and mammals existed.

A large part of its skull was one of many animal fossils found entangled in the roots of a huge, ancient, stony tree trunk clinging to a seaside cliff on Cape Breton Island.

Award-winning amateur paleontologist Brian Hebert This stump, found about nine years ago, is about three or four meters wide. TyrannoroterName of the species, hebertyRespects him.

Mann worked with Hebert and helped excavate the stump during her PhD with paleontologist Hilary Maddin of Carleton University.

TyrannoroterThe skull appears to belong to a group of microsaurs called pantilids, says Mann, curator of early tetrapods and fossil fish at the Field Museum of Natural History in Chicago.

Complete bodies of similar specimens that were about 20 million years younger, such as an animal called PantylusFirst described by paleontologists. They have short, squat bodies with large rib cages and adaptations for digging. Mann says he believes the Tyrannorotor would have looked similar.

Most panthelids were small – only five or 10 centimeters long. researchers think Tyrannoroter It was huge by comparison – about the size of a football. That’s why they named it this TyrannoroterMeaning “tyrannical digger.”

plant eating pioneers

TyrannoroterIts most distinctive feature is several rows of teeth that Mann describes as “Hershey-kiss” shaped teeth. He says they were ahead of their time – adapted to eating shoots, leaves and other high-fibre plants.

“This is the oldest animal known to have teeth of this type,” he told CBC News. The teeth are similar in shape to those of insect-eating animals, but additional rows or “batteries” provide the surface area needed for grinding them.

Mann says this is why humans, who also eat vegetables, have flat tops on their molars.

Four-legged animals first arrived on land about 375 million years ago, during the Devonian, the period before the Carboniferous.

At that time, plants, which had originated on land 100 million years ago, were abundant. But tetrapods had neither the teeth to chew them nor the ability to digest them – which would normally require teaming up with gut microbes that could break down cellulose.

That process requires a larger intestinal cavity to make room for it, Mann said. This is why many modern herbivores like cows and hippos (and herbivorous dinosaurs like Triceratops) are big and chubby.

While tetrapods in the Devonian and early Carboniferous could not eat plants, at that time the leaves already had damage that suggests they were being eaten by insects.

Mann and colleagues suggested ancestors of animals such as Tyrannoroter They probably gained the ability to digest cellulose by eating those insects.

And they suggest that the wide, squat bodies of pentilids may be evidence that they had cellulose-digesting microbes in their intestines.

Mann says there are a lot of vegetarians and vegans in her own family, and “it’s good to know” how long ago animals were experimenting with such diets.

Knowing when herbivores emerged is also useful for scientists studying evolution, he said, because herbivores have a huge impact on plants and their ecosystems.

Robert Reese is a paleontologist at the University of Toronto Mississauga Researched the origin of herbivorous diets in other early tetrapodsBut was not included in the new study.

He said that this paper is very good for Canadian paleontology, and also suggested Tyrannoroter Whether he was a vegetarian “is an interesting idea worth further investigation.”

For example, he suggests looking for scratches on the teeth that can tell you which direction its jaw or teeth were moving while chewing plants. He acknowledged that researchers had found wear on the tops of teeth, but that it could have been caused by eating other hard materials.

He also says that he does not think it is possible to predict TyrannoroterHis body shape is based only on his skull.

Previously, the oldest tetrapod to show evidence of herbivory was desmatodonWho lived approximately 303 to 306 million years ago.

If Tyrannoroter Also being a vegetarian, Reese said, “it will push that timeline back, but only a little bit.”