A recently identified creature, about the size of a football, with the ability to chew like a dedicated plant-eater, may be one of the earliest herbivores among vertebrates. The creature, named Tyrannoroter heberti, roamed the Earth approximately 307 million years ago during the late Carboniferous Period in a lush, fern-filled swamp on what is now Cape Breton Island, Nova Scotia. During that era, most tetrapods, four-legged animals, primarily consumed other animals as they had not yet developed the means to consume and digest plant materials like leaves and bark.
According to a recent study, Tyrannoroter heberti is the earliest known four-legged animal equipped with teeth suitable for a plant-based diet. This discovery challenges previous notions about the pace at which this dietary transition occurred, as mentioned by Arjan Mann, the lead author of the study published in Nature Ecology and Evolution.
Belonging to the microsaur group, Tyrannoroter was a small, lizard-like creature from a time predating the existence of reptiles and mammals. Fossils of this species were unearthed entangled in the roots of a large, ancient petrified tree stump on Cape Breton Island, discovered by amateur paleontologist Brian Hebert approximately nine years ago. The species name, heberti, is a tribute to him.
The skull of Tyrannoroter resembles that of pantylids, a group of microsaurs known for their short, squat bodies with adaptations for digging. Despite most pantylids being tiny, Tyrannoroter stood out due to its larger size, comparable to a football, hence its name meaning “tyrant digger.”
A distinctive feature of Tyrannoroter is its multiple rows of “Hershey-kiss” shaped teeth, uniquely adapted for consuming shoots, leaves, and fibrous plant matter. These teeth, resembling those of insect-eating animals, stood out due to the additional rows or “batteries” that provided the necessary surface area for grinding.
Further analysis of fossils related to Tyrannoroter suggests that this group of animals began specializing in plant-based diets even earlier, indicating an evolutionary shift towards herbivory. The research sheds light on the transition of tetrapods from primarily carnivorous diets to herbivorous preferences during the Carboniferous Period.
Understanding the emergence of herbivores is crucial in evolutionary studies, as herbivores play a significant role in shaping plant ecosystems. This discovery contributes to the broader understanding of early tetrapod evolution and highlights the complex dietary adaptations that occurred in vertebrate history.