Introducing Tyrannoroter heberti, a recently cataloged species that represented one of the era’s most imposing terrestrial fauna, at least from the perspective of ancient flora. Originating approximately 307 million years ago, this distinctive tetrapod stands as one of the earliest identified terrestrial organisms to adopt a herbivorous feeding strategy.
By the period when the initial vertebrates transitioned from aquatic to terrestrial environments, roughly 370 million years ago, plant life had enjoyed over a hundred million years of relatively undisturbed existence on land.
Fortuitously for the flora, these early vertebrate fauna appeared content with consuming one another for extensive periods; however, it was an inevitable evolutionary development that something would arise to exploit this abundant novel food source.
Computed tomography scans of its cranial structure indicated that Tyrannoroter was among the first creatures to master this dietary shift. Its dentition and mandibular apparatus were demonstrably well-suited for subsisting primarily on a plant-based regimen.
“This represents one of the most ancient known quadrupedal creatures to consume vegetation,” remarks Arjan Mann, an evolutionary biologist affiliated with the Field Museum in Chicago and a joint principal investigator of the research detailing this discovery.
“It substantiates that the exploration of herbivory extends back to the very inception of terrestrial tetrapods – the ancestral lineage encompassing all land vertebrates, ourselves included.”
Notwithstanding its formidable appellation, Tyrannoroter likely measured no more than approximately 25 centimeters (10 inches) in length. It is presumed to belong to a clade of organisms known as pantylids, which were kin to the common progenitor of both reptiles and mammals.
“The pantylids emerged during the second epoch of terrestrial adaptation, a phase characterized by the permanent acclimatization of fauna to life on solid ground,” states Mann.
Paleontologists unearthed the skull of Tyrannoroter within an petrified tree trunk located in Nova Scotia, Canada. The investigators involved in the contemporary study employed high-resolution micro-CT scanning techniques on the specimen to decipher the narrative conveyed by its dentition.
In addition to a conventional row of teeth along the mandible, Tyrannoroter possessed specialized dental plates, referred to as dental batteries, situated on the palate and within the lower jaw. As observed in numerous subsequent herbivorous species, including dinosaurs, these structures would have facilitated the mastication and pulverization of recalcitrant plant matter.
“Our greatest anticipation was to ascertain what lay concealed within this creature’s oral cavity upon scanning – a mouth replete with an auxiliary array of teeth designed for the crushing and grinding of sustenance, such as plants,” exclaims Hillary Maddin, a paleontologist at Carleton University in Canada and the senior author of the research paper.
While Tyrannoroter may have been primarily vegetarian, it is unlikely to have been strictly vegan, according to the researchers. It probably would not have eschewed opportunities to consume insects or arthropods if presented.
Indeed, its propensity for a herbivorous diet might have its origins in its ancestors’ consumption of such invertebrates. Dental batteries could have initially evolved as a mechanism for fracturing tough exoskeletons, prior to an opportunistic organism discovering their utility in processing vegetation.
Furthermore, given that insects themselves subsisted on plants, their consumption could have equipped the tetrapods’ digestive tracts with the requisite microbiota for breaking down cellulose.
“These findings, corroborated by other recent investigations, furnish direct empirical evidence that reshapes our understanding of the timeline for the emergence of herbivory, indicating that diverse herbivorous morphologies appeared rapidly subsequent to the terrestrial colonization by tetrapods,” the researchers articulate.
The study has been published in the esteemed journal Systematic Palaeontology.
