A newly identified dinosaur the size of a modern turkey has earned the nickname hell chicken, and researchers say its skull shows it was built to eat fruit rather than flesh or leaves. The toothless creature, formally named Infernogallus jamesi, lived during the final chapter of the dinosaur era and has been singled out as the first known dinosaur specifically to have eaten fruit.
An international research team identified the newly discovered species, with the work led by Stony Brook University paleontologist Greg Funston, according to Stony Brook University. The paleontologists were affiliated with Stony Brook, the Royal Ontario Museum and the North Dakota Geological Survey, and their findings were published online in Nature Communications on October 10, as Sci.News reported. News12 New York reported that the species name itself translates to hell chicken, a nod to the formation where its bones turned up.
Fossils From Montana's Hell Creek
Infernogallus jamesi's fossils were uncovered in the Hell Creek Formation, a fossil-rich layer that extends across Montana, North Dakota, South Dakota and Wyoming. The specimen, which included a nearly complete skull and partial skeleton, was collected in 2011 from the Montana portion of the formation, per the Sci.News account. Researchers describe it in their published paper as a diminutive caenagnathid oviraptorosaur, according to the study published in Nature Communications.
The animal belonged to caenagnathids, a group of toothless, feathered dinosaurs, and stood about the size of a modern turkey. Stony Brook University's release puts its likely weight at roughly 12 kilograms, or 25 pounds, while Sci.News cites an estimate of 12 kilograms, or 26 pounds, for the same animal. It lived alongside T. rex, Triceratops and Ankylosaurus in the same Cretaceous ecosystem, sharing ground with some of the era's most fearsome predators and armored herbivores.
A Skull Unlike Any Other Dinosaur's
The research team analyzed the dinosaur's exceptionally preserved skull, which the Nature Communications paper describes as a nearly complete, articulated skull. That skull had a unique jaw structure not previously documented in dinosaurs, one that evolved to crush fleshy fruits and separate edible pulp from large seeds. CT-scan analysis showed the lower jaw could slide forward and backward by up to about 15 millimeters, a motion that supported oral processing of soft foods, according to Sci.News.
Infernogallus also had chewing muscles arranged similarly to those of modern parrots and was specialized for crushing and processing soft fruits. Scientists interviewed by Science noted that, among modern birds, the only group combining all of those anatomical specializations is obligate fruit-eating parrots. The same report indicates the dinosaur was likely adapted to process drupes, fruits with a hard central seed or pit surrounded by softer flesh. Sci.News adds that the closest living dietary match identified by researchers was the Pesquet's parrot, which mashes fruit pulp and discards the seeds.
Scientists Say the Find Caught Them Off Guard
Funston said the team did not expect to discover fruit-eating dinosaurs when the research began. He added that the skulls of these animals had gone undocumented for more than a century and turned out to be far stranger than anticipated. Infernogallus evolved from the broader theropod family that includes meat-eating dinosaurs such as T. rex, making it a distant relative of the tyrant lizard despite its dramatically different diet.
Dr. David Evans said the unusual skull offers insights into dinosaur evolution and feeding specialization. He also said scientists still have much to learn about the world of T. rex and the dinosaurs that shared that landscape. The study concludes that caenagnathids as a group were specialized herbivores whose diets likely consisted largely of fleshy angiosperm fruits, per the Nature Communications paper.
A Changing Cretaceous Landscape
The researchers link the evolution of caenagnathid herbivory to the rise of fleshy angiosperm fruits in the Late Cretaceous. During the period when Infernogallus lived, flowering plants spread across the landscape and replaced cone-bearing plants that had dominated for millions of years, and forests grew richer in fruits and seeds. Findings cited by Smithsonian Magazine suggest flowering plants were already producing relatively large fruits nearly 75 million years ago, about 10 million years earlier than previously estimated.
Researchers say fruit-eating dinosaurs like Infernogallus may have helped spread flowering plants by dispersing their seeds, potentially shaping prehistoric ecosystems in ways not previously recognized. Still, a review of the study by Eigenradar cautions that the comparison between caenagnathid diversification and flowering-plant fruit diversification does not establish causal coevolution between the two. Elsewhere in the fossil record, the early bird Jeholornis has been identified as the earliest-known fruit-eating animal, living roughly 120 million years ago and apparently swallowing whole fruits, seeds included, according to the Field Museum. Infernogallus jamesi now stands as a very different kind of pioneer, the first dinosaur whose skull tells scientists it was built specifically for a fruit-based diet.
