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Dinosaurs ate a lot of things, including each other. Fruit, scientists long assumed, was not on the menu. A turkey-sized, toothless dinosaur from the twilight of the age of dinosaurs has just proved that assumption wrong.
According to reports from Reuters via GMA News and Stony Brook University, the new species, Infernogallus jamesi, is the first known dinosaur that specifically ate fruit. Its fossils were found in Montana and North Dakota, in the Hell Creek Formation — hence the name, which means "hell chicken."
A parrot's jaw on a dinosaur's body
Infernogallus lived about 66 million years ago, during the Cretaceous Period, in the subtropical coastal floodplain it shared with Tyrannosaurus, Triceratops and the tank-like armoured plant-eater Ankylosaurus. It was about 5 feet (1.5 metres) long and weighed around 25 pounds (about 12 kg) — roughly the size of a turkey, and one of the smallest members of its group even as a fully grown adult.
It belonged to a group of toothless, feathered dinosaurs called caenagnathids, a type of small oviraptorosaur. The fossils — one nearly complete skeleton and isolated bones from a jaw and palate, now on display at the Royal Ontario Museum — did not themselves reveal feathers, but researchers believe the animal was covered in them, based on fossils of close relatives.
What sets Infernogallus apart is its mouth. Led by palaeontologist Greg Funston of Stony Brook University, the team analysed the chewing muscles of the new species and found a unique arrangement seen today only in fruit-eating parrots. Three features matter most, Funston said: jaw muscles organised to power back-and-forth chewing motions, a mobile joint that let the jaw slide forward, and a series of ridges and grooves on the beak to help mash and shear soft plants like fruits.
Using CT scans to reconstruct the skull, the researchers found that the bones of the palate arched downwards into the mouth itself, making certain muscles face front-to-back instead of up and down. Detailed analysis showed the skull was specialised for mashing stone fruits to remove the flesh from the main seed — the same mechanical problem a modern parrot solves with its beak.
Why a fruit-eating dinosaur rewrites two stories
The first story is about dinosaurs themselves. It had been proposed before that some groups ate fruits, but there was never evidence to back it up, according to study co-author Thomas Dudgeon, a postdoctoral researcher at the Royal Ontario Museum. Infernogallus provides that evidence — and it is surprising because the animal evolved from the meat-eating side of the dinosaur tree. A lineage of predators produced, at the very end of the Cretaceous, a dedicated fruit specialist.
The second story is about plants. During the Cretaceous, flowering plants — angiosperms, which first appeared around 130 to 140 million years ago — took over from cone-bearing plants as the major vegetation on land. Fruits are the reproductive structures of flowering plants, and animals that eat fruit and disperse seeds help those plants spread. The discovery suggests dinosaurs may have had an unrecognised impact on the evolution of flowering plants as seed dispersers, a role previously credited almost entirely to birds and mammals after the dinosaurs died out.
The fruit available to Infernogallus may have included various berries as well as drupes — a broad category that today includes types with a central pit like peaches and cherries, as well as mangoes and olives. Those modern examples illustrate the kind of fruit, not a claim that this dinosaur ate peaches.
The research was published in the journal Nature Communications. It leaves one delicious irony intact: the most famous residents of Hell Creek were apex predators. The animal that may have done the most for the future of plant life there was a 25-pound chicken that chewed its fruit.