A turkey-sized 'hell chicken' dinosaur was built to eat fruit, a skull study finds

A small, feathered dinosaur that lived alongside Tyrannosaurus rex was specialized for eating fruit, according to a study of its skull, the Royal Ontario Museum (ROM) said on 28 October. The new species, Infernogallus jamesi, nicknamed the “hell chicken,” is described in Nature Communications.

A toothless dinosaur with a parrot’s bite

Infernogallus was a caenagnathid oviraptorosaur, part of a family of toothless, feathered dinosaurs. It was about the size of a turkey and weighed roughly 12 kg. Its fossils, a nearly complete skull and a partial skeleton, come from the Hell Creek Formation, which spans parts of Montana, North Dakota, South Dakota and Wyoming, and date from the end of the Cretaceous period. They are now on display at the ROM in Toronto.

CT scans of the skull showed chewing muscles arranged in a way seen today only in fruit-eating parrots. The bones in the roof of the mouth arch downward, which allowed forward-facing muscles and a sliding, front-to-back chewing motion. The researchers concluded the skull was built to mash stone fruits and strip the flesh from the seed.

“It's pretty rare for animals to become specialized for a diet of fruit.” — Dr. Thomas Dudgeon, Royal Ontario Museum

Weirder than expected

Caenagnathids were already known as unusual, toothless dinosaurs. “We never expected to discover fruit-eating dinosaurs,” said lead researcher Dr. Greg Funston of Stony Brook University. “Now, we know they were even weirder than we could have predicted.”

The study was led by Funston with Dr. Thomas Dudgeon, a postdoctoral fellow at the ROM, and senior author Dr. David Evans, the museum's chief curator of natural history, together with researchers from the North Dakota Geological Survey. The evidence comes from the anatomy of the skull; the museum did not report fossilized fruit or seeds with the specimen.

A new look at the world of T. rex

“This discovery shows that we still have a lot to learn about the world of T. rex,” Evans said. Other recent fossil finds include a 75-million-year-old ‘ostrich dinosaur’ from Utah.