Paleontologists have made a groundbreaking discovery, providing the first conclusive evidence that pterosaurs, the extinct flying reptiles that soared through the Mesozoic Era, consumed plants. By analyzing fossilized stomach contents, researchers from China and Brazil have identified hundreds of microscopic plant particles – called phytoliths – within the fossil of a pterosaur species called Sinopterus atavismus. This finding significantly expands our understanding of these ancient creatures and challenges previous assumptions about their diets.
The Mystery of Pterosaur Diets
Pterosaurs, which existed alongside dinosaurs, are renowned for being the earliest vertebrates to evolve powered flight. Despite their impressive aerial abilities, much about their lifestyle remains a puzzle, particularly their dietary habits. While various theories have been proposed – ranging from insect-eating and fish-catching to carnivory and even filter-feeding – definitive proof has been elusive.
Rare Finds: Stomach Contents and Previous Discoveries
Direct evidence of a pterosaur’s diet is exceptionally rare: fossilized stomach contents are incredibly difficult to find and preserve. Until now, only five confirmed cases of pterosaur stomach contents were known, all from the Late Jurassic period and all belonging to the Rhamphorhynchus species found in Germany. These remains primarily consisted of fish bones, with some unidentified objects. This new discovery adds a crucial piece to the puzzle, revealing a different, unexpected dietary preference.
The Sinopterus atavismus Finding
The current study focused on a fossil of Sinopterus atavismus, a type of tapejarid pterodactyloid pterosaur that lived in China approximately 120 million years ago. Researchers meticulously examined the fossilized stomach contents and extracted an impressive 320 phytoliths – microscopic, rigid bodies made of mineral deposits that form within plant cells. These tiny structures offer a detailed picture of the pterosaur’s last meals.
“This discovery marks both the first phytolith extraction from any pterosaur and the second documented pterosaur specimen containing gastroliths,” the researchers noted.
Ruling Out Other Possibilities
To ensure the findings were truly representative of a plant-based diet, the researchers rigorously investigated alternative explanations. They first confirmed that the phytoliths weren’t contaminants from the surrounding rock. Next, they considered whether the plant material could have come from consuming other plant-eating animals. However, Sinopterus atavismus possessed a bird-like metabolism, and the absence of bones, scales, or insect shells eliminated this possibility. The idea that the pterosaur consumed soft-bodied creatures like caterpillars also didn’t hold up; the presence of gastroliths (small stones used for grinding) suggests the need to break down tough plant material, a process unnecessary for digesting soft prey.
Supporting Evidence: Strong Jaws and Related Species
Further bolstering the case for herbivory, previous studies of Tapejara wellnhoferi – a close relative of Sinopterus atavismus – revealed strong jaws well-suited for eating plants. This, combined with the phytolith and gastrolith evidence, paints a clear picture of Sinopterus atavismus as a plant-eater.
“Therefore, the phytoliths represent direct dietary intake, while the gastroliths functioned as grinding tools for plant material processing,” the researchers concluded.
The findings, published in the October 15, 2025 issue of the journal Science Bulletin, dramatically alter our understanding of pterosaur diets and highlight the diversity of feeding strategies within this fascinating group of extinct flying reptiles. This discovery underscores how even long-extinct animals can reveal unexpected details about their lives, thanks to dedicated research and careful analysis
