Fruit-eating dinosaur Infernogallus jamesi ID'd for first time by research team with Stony Brook paleontologist - Newsday

Some 68 million years ago on the warm subtropical flood plain of what would become Montana and North Dakota, a birdlike, bipedal dinosaur evolved alongside its famous cousin, Tyrannosaurus rex.

Unknown to science until recently, this turkey-sized creature had unusual appetites and a specialized anatomy to match: It was, paleontologists say, the first dinosaur believed to have subsisted on fruit, employing a ridged and grooved beak with a top jaw that worked like a citrus juicer. It mashed its meals with a horizontal motion unlike that of carnivores, which used great vertical force to rip their meals apart, or most other herbivores, which ground tough and fibrous plant matter.

A team of researchers including Stony Brook University paleontologist Gregory Funston identified the new genus and species in a paper published online Oct. 10 in the journal Nature Communications, working from five fossil specimens, including the first intact skull for a dinosaur family of its kind. They named the dinosaur Infernogallus jamesi, or "Hell Chicken," a designation that refers to its discovery in the Hell Creek Formation of the American West and the animal’s birdlike appearance, not to its temperament. Paleontologists from the Royal Ontario Museum and the North Dakota Geological Survey also participated in the project. 

Since the turn of the century, new dinosaur species have been discovered at a rate of slightly less than one per week. But I. jamesi is special, said Stuart S. Sumida, biology professor at California State University San Bernardino and president of the Society of Vertebrate Paleontology, who was not involved in the project.

“What’s very unusual, first of all, is to have a plant-eating animal” shown to be related to a group of carnivores including T. rex, Sumida said. “It shows how plastic evolution can be.”

Equally important, Sumida said, is the “evidence for how [I. jamesi] interacted with its environment and its ecosystem,” pointing to ways in which “evolution is not restricted to individual groups of organisms, but entire ecosystems that evolve as organisms interact with one another.”

I. jamesi emerged at the end of the Cretaceous period as fruit-bearing plants were exploding in diversity, a phenomenon known as the Cretaceous Terrestrial Revolution. The fruit eater probably benefited from the variety of plants and the increase in the size of the fruits.

The plants also benefited, because “plants don’t run around,” Sumida said. “Well, if you have herbivores eating and scattering the seeds away from the place where the fruit is consumed, this is a tremendous way” for the plants to disperse. I. jamesi was almost certainly not the only dispersal vector, “but it’s our best new example of how that was done in the Cretaceous,” Sumida said.

Thomas R. Holtz Jr., principal lecturer in vertebrate paleontology at the University of Maryland, who was not involved with the project, said the fossils Funston and his colleagues worked on were some of the most complete ever found for oviraptors, the larger group to which I. jamesi belongs. “Before, you might find a jaw here, a backbone there, an arm there, so you can see they’re probably the same type of dinosaurs, but you don’t know the proportions.” Now that paleontologists have a “ground truth” or baseline, Holtz said, they can more precisely identify new specimens from the field or fossils that are already in collections but unidentified.

The Nature Communications paper describes its subject’s skull as “bizarre.” In an interview, Funston, who is also an assistant professor in the Renaissance School of Medicine’s anatomical sciences department, said: “Nothing prepared me for how unusual this animal looked.” Areas in the skull where paleontologists might have expected jaw muscles to take up space had, in the course of evolution, “completely shrunk down and closed up,” suggesting that the muscles had “almost withered away,” and the palatal bones from the roof of the dinosaur’s mouth dipped down “so far into the mouth cavity that when the mouth closed, you would have been able to feel the roof of the mouth under the chin.”

The only animals with vaguely similar anatomy and muscle mechanics are the green sea turtle, which eats jellyfish and sea grass, and the vulturine parrot, which eats mainly figs, Funston said. There is no direct lineage; the species evolved the traits independently, a phenomenon known as convergence, he said.

Scientists believe that I. jamesi weighed about 25 pounds. It was not a direct ancestor of birds and was flightless, but “you would struggle to distinguish it from a bird if it were alive today,” Funston said. “It had big eyes, a short, parrotlike face, a long neck like an emu, and it was covered in feathers.”

The fruit I. jamesi ate would have been “juicy and would have had a good amount of sugar,” Funston said, though it would not necessarily have been as sweet as much of what humans eat today. The species would have been prey for carnivores like T. rex.

I. jamesi’s time in the sun, like T. rex’s, was geologically fleeting. The city-sized asteroid that hit the Earth 66 million years ago killed off three-fourths of all life, including dinosaurs, except birds, which may have survived, in part, because they had flexible eating habits.

Fruit-eating I. jamesi, by contrast, had evolved for a niche in a complex ecosystem that no longer existed. “You have the rug pulled out from under you,” Funston said. “You have no chance to respond.”