Fossilized gut contents elucidate the feeding habits of sauropod dinosaurs

Sauropod dinosaurs were abundant and diverse across much of the globe throughout the Jurassic and Cretaceous periods and include the largest terrestrial animals of all time. Since the discovery of the first near-complete skeletons in the late 19^th century, sauropods have been almost universally interpreted as herbivorous. However, our concept of their diet is based on indirect evidence and inference since no sauropod fossilized gut contents (cololites) are known. Here, we describe a cololite associated with a specimen of the sauropod Diamantinasaurus matildae from the mid-Cretaceous (∼101-94 Ma) Winton Formation of Queensland, Australia. The cololite is hosted within an indurated rock layer, localized to the abdominal region, and closely and consistently associated with a layer of mineralized skin. Conifer pinnules, angiosperm leaves, and seed-fern fruiting bodies are preserved within, as are chemical biomarkers consistent with gymnosperms and angiosperms. This Diamantinasaurus cololite provides the first direct, empirical evidence in sauropods of herbivory, demonstrating generalist feeding, low- to high-level browsing, and minimal oral processing of food. The longevity of the clade Sauropoda was underpinned by the persistence through time of generalist feeders like Diamantinasaurus that were capable of feeding at a range of heights on a variety of different plant species.