More than 65 million years ago, a small, beaked dinosaur dubbed the “hell chicken” was a real terror – to fruit. Reconstruction of its beak and jaw suggest it mashed up fruit much like modern parrots.
It’s the first evidence of non-avian dinosaurs evolving specialized adaptations for eating fruit, and comes at a time when flowering plants were coming into their own, researchers report October 10 in Nature Communications.
In 2011, a fossil collector found much of the fossilized skeleton of an odd theropod dinosaur in eastern Montana and brought to the attention of David Evans, a paleontologist at the Royal Ontario Museum in Canada. Over the next several years, fossil collectors and paleontologists working in Montana and North and South Dakota unearthed four more partial skeletons.
The dinosaur belonged to a particularly birdlike subgroup of beaked theropods called oviraptorosaurs that lived during the Cretaceous Period. This species probably weighed around 12 kilograms — about the size of a turkey.
Evans and Greg Funston — a paleontologist at Stony Brook University in New York — and their colleagues named it Infernogallus jamesi, or ‘hell chicken,’ after its discovery in the Hell Creek geological formation and its overall poultrylike appearance.
When the researchers studied Infernogallus’s skull and reconstructed the musculature, they discovered that it was no ordinary theropod. The construction of its jaw joints, muscles and palate suggest that it moved its jaw forward and back when eating rather than up and down like its chomping relatives.
This chewing style is unique among non-avian dinosaurs but is strikingly similar to that of fruit-eating parrots. Funston and his colleagues think Infernogallus had adapted to a fruit-rich diet, deftly stripping the flesh from large seeds using its tongue and sliding jaw motions.
These fruit-munching adaptations were surprising, Funston says. “But the more we delved into it, the more sense it made,” he says. “All the different lines of evidence seemed to converge on this one answer.”
Angiosperms — plants that produce flowers and fruits — were rapidly diversifying throughout the Cretaceous. Mounting evidence suggests that angiosperms were coevolving with Cretaceous animals, and that dinosaurs may have been eating their fruits. Infernogallus adds to that emerging picture. It’s possible that other ‘hell chicken’ relatives or other dinosaur groups were habitual fruit eaters too, Funston says.
“[The discovery] suggests that our picture of dinosaur ecology right before the Cretaceous extinction has been missing major puzzle pieces, and that dinosaurs were more diverse than we thought.”
