Dinosaurs ate many different things, including one another, but fruit appears to have been missing from the menu. Scientists have now found fossils of a toothless, beaked species the size of a turkey, with a parrot-like head, that appears to have been adapted to a diet of fruit.
The first known fruit-eating “chicken dinosaur”
The species, named Infernogallus jamesi, lived 66 million years ago during the Cretaceous period, at the very end of the age of dinosaurs. Its beak and jaw show signs that it preferred soft food such as fruit. It is known from fossils found in Montana and North Dakota.
The name Infernogallus means “hell chicken”. The animal resembled a bird, and its fossils were found in the Hell Creek Formation, a rock formation that stretches across the US states of Montana, Wyoming, North Dakota and South Dakota. The remains of some of the world’s most famous dinosaurs have been found there.
Sharing a habitat with Tyrannosaurus
Scientists believe the dinosaur ate fruit and other soft plants in what was then a subtropical coastal floodplain ecosystem. It shared this habitat with top predators such as Tyrannosaurus, and with other plant-eaters such as Triceratops and Ankylosaurus.
Infernogallus was 1.5 metres long and weighed about 11.3 kilograms. The fossils are a nearly complete skeleton plus individual bones from a jaw and a palate. They do not show whether it had feathers, but scientists believe it was covered in them, based on fossils of its close relatives.
It belonged to the theropods, mostly meat-eating dinosaurs that are the ancestors of modern birds.
“This shows us how adaptable theropods were,” said palaeontologist Greg Funston of Stony Brook University in New York, lead author of the study published in the scientific journal Nature Communications.
A link with flowering plants
Fruits are the reproductive structures of angiosperms, or flowering plants. Angiosperms first appeared slightly earlier in the Cretaceous, 130 to 140 million years ago, and spread across areas previously dominated by gymnosperms such as conifers.
The case of Infernogallus shows that some dinosaurs may have had a close ecological relationship with flowering plants.
“It had been suggested in the past that some dinosaurs may have eaten fruit, but there was never any evidence for it,” said co-author Thomas Dudgeon, a postdoctoral researcher at the Royal Ontario Museum in Toronto.
“The discovery of Infernogallus shows that dinosaur diets were far more varied than we thought. Before this discovery, there was some mystery about their evolution. The appearance of flowering plants introduced an entirely new food source that undoubtedly affected animals,” he added.
The fruits available to the “hell chicken” included various kinds of berries and drupes. Today, drupes range from peaches and cherries to mangoes and olives.
Three features that point to fruit
Infernogallus had several features that indicate a fruit-eating diet. According to Mr Funston, the three most important were:
- Jaw muscles arranged for back-and-forth chewing movements
- A mobile joint that allowed the jaw to slide forwards
- A series of grooves in the beak that helped mash and cut up soft plants
Some animals alive today have features like these, such as the vulturine parrot, which eats figs, and sea turtles that feed on seagrass. However, no living animal has all three, Mr Funston explained.
Beaks versus teeth
Infernogallus also shows how much more adaptable beaks are than teeth.
“If you lose your teeth and grow a beak in their place, the range of food available to you increases dramatically, as long as you have a way to digest it,” Mr Funston said.
Most plant-eating theropods used gastroliths, swallowing stones to grind food in their stomachs. Infernogallus and other members of its family chewed their food instead.
Spreading seeds
Fruit-eating animals also play an important role in the spread of flowering plants because they disperse seeds.
“Mammals and birds probably also ate fruit, but for them it was a less important food source. Also, during the Cretaceous, mammals and birds were relatively small, so they were unlikely to disperse large seeds or carry them over long distances,” Mr Funston explained.
Source: ANA-MPA
