A study published in Current Biology provided evidence that sauropod dinosaurs were herbivores. The research team analyzed the fossilized abdomen of a sauropod, revealing plant fossils that served as the dinosaur's last meal. The discovery offers the first proof of the dietary habits of these ancient giants.
The scientists identified conifer foliage, seed ferns, and angiosperm leaves—flowering plants—within the fossilized gut contents, confirming their herbivorous diet. The finding supports long-held hypotheses about these enormous creatures that roamed the Earth millions of years ago.
"This finding confirms several hypotheses about the sauropod diet that had been made based on studies of their anatomy and comparisons with modern-day animals," said Dr. Stephen Poropat, a paleontologist and the lead author of the study from Curtin University in Australia. The preserved plants showed evidence of being cut or bitten but not chewed, indicating that sauropods swallowed their food whole and relied on gut fermentation for digestion.
The specimen studied, nicknamed "Judy," is a subadult Diamantinasaurus matildae that lived approximately 94 to 101 million years ago during the mid-Cretaceous period. Unearthed in 2017 in the Winton Formation of Queensland, Australia, Judy represents the most complete sauropod skeleton and the first with fossilized skin ever found in Australia. The Australian Age of Dinosaurs Museum of Natural History led the excavation, assisted by volunteers and staff.
The discovery of fossilized intestinal contents within Judy marks a world-first in paleontology. Prior to the discovery, scientists had not found direct evidence of sauropod stomach contents, despite their presence across all continents for about 130 million years. The coprolite—the fossilized gut contents—contained well-preserved plant remains, providing insights into the diet and feeding behavior of sauropods.
Analysis of the gut contents revealed that Judy consumed vegetation including conifer bracts from tall trees like araucarias and austrosequoias, seed pods from extinct seed ferns, and leaves from angiosperms. The presence of angiosperms in the diet was surprising, as these flowering plants had only recently appeared in the fossil record. "Angiosperms became approximately as diverse as conifers in Australia around 100 million to 95 million years ago, when this sauropod was alive," noted Poropat, according to Popular Science.
The study also shed light on the feeding strategies of sauropods. The minimal chewing of food and reliance on gut fermentation suggest that sauropods were indiscriminate bulk feeders, consuming any plants they could reach and safely process. The feeding behavior likely contributed to their ability to grow to enormous sizes and their success as a clade over millions of years.
Understanding sauropod diets is crucial for reconstructing prehistoric ecosystems and the roles these giants played within them. Their feeding habits would have had impacts on vegetation patterns, plant evolution, and the overall dynamics of their environments. The findings largely corroborate past ideas regarding the enormous influence that sauropods must have had on ecosystems worldwide during the Mesozoic Era.
While the discovery provides valuable insights, Poropat cautioned against generalizing the findings to all sauropods. "We do not know if the preserved plants in our sauropod represent its typical diet or the diet of a stressed animal," he stated, according to a press release published on EurekAlert. Furthermore, seasonal variations and differences between juvenile and adult diets remain areas for future research.
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