A small dinosaur's jaw offers clues to its menu
· BehindLines newsroom
An almost complete skull offers a clue to a dinosaur's meals: Infernogallus jamesi may have been adapted to a diet rich in fleshy fruit. Stony Brook University presented the research on 28 October. The accepted, peer-reviewed scientific paper had already appeared online in Nature Communications on 10 October, in a version still subject to editorial changes.
What the fossil preserves
The study's abstract describes a small caenagnathid oviraptorosaur. Its skull, with the bones still articulated, allows researchers to reconstruct an arrangement of muscles unusual among non-avian theropod dinosaurs.
The authors propose that this arrangement allowed the lower jaw to move backwards and forwards. Opposing ridges could thus have helped process soft food in the mouth. They compare this organisation with that of living parrots that eat fruit.
The conclusion concerns an anatomical adaptation and the diet it makes plausible. It is not a direct observation of the animal eating. Scientific abstract accessible through the publisher's PDF link.
From scans to interpretation
Stony Brook's account explains that the team used computed tomography to reconstruct the skull. Bones in the palate curved down into the mouth, changing the orientation of certain muscles.
The university places the fossils in the Hell Creek Formation in the United States. It describes a turkey-sized animal with an estimated mass of about 12 kilograms and says that the skull and part of the skeleton are displayed at the Royal Ontario Museum.
Fruit, and then the question of seeds
The scientific abstract links the proposed specialisation to the diversification of fleshy fruits produced by flowering plants. Stony Brook also discusses a possible role in spreading seeds.
That second idea remains a research question: the paper states that these dinosaurs' role in the proliferation of fruit is uncertain. A jaw adapted to soft foods therefore does not, by itself, establish the full history of their relationship with plants.