Jeholornis: When Seeds Point to Fruit

Jeholornis specimen STM3–8 preserves a largely articulated skull, compressed in rock with some bones displaced. Researchers used the Australian Synchrotron to image the bones and digitally reconstruct their arrangement, with instrument scientist Joseph Bevitt assisting the work.

The specimen came from Dapingfang in the Chaoyang region’s Longcheng District, in the Jiufotang Formation, around 120 million years old. It belongs to the Shandong Tianyu Museum of Nature in Pingyi, not to a museum at its findspot. The reconstruction brought a Liaoning fossil from a Shandong collection into an international imaging project.

Seeds had encouraged an interpretation of Jeholornis as a seed eater. But a bird can swallow a seed while eating the fleshy material around it. It can also crack a seed in its beak or grind it after swallowing. These behaviours leave different evidence.

In the 2022 study led by Han Hu, the reconstructed skull was compared with modern birds from different feeding groups. Its shape did not fit the previously suggested powerful seed-cracking apparatus. Skull shape alone, however, could not settle every alternative. The team also examined what modern birds’ abdominal contents look like under imaging.

Published Jeholornis specimens preserved intact seeds without the damage expected from grinding. Other specimens contained gastroliths, swallowed stones associated with digestive processing, but the study did not find them together with the seed assemblages. That combination supported at least seasonal fruit consumption, with other foods used at other times.

The comparison drew on several fossils: STM3–8 supplied the reconstructed skull, while other numbered specimens preserved the seeds or gastrolith masses. Anatomical shape and the condition of abdominal contents independently contributed to the dietary interpretation.

The paper uses fruit in a broad ecological sense that includes fleshy coverings around gymnosperm seeds, as well as the fruits of flowering plants. This definition links the dietary interpretation to the seed-bearing plants of the Early Cretaceous.

It also suggests a possibility beyond diet. If seeds survived passage through the bird, movement and excretion could have helped disperse plants. Seed dispersal remains a potential consequence of the inferred feeding behaviour. The resulting picture is of a long-tailed early bird interacting with plants, with food available seasonally rather than one exclusive diet for its entire life.