New research analyzing fossilized digestive materials, known as bromalites, sheds light on how dinosaurs evolved to dominate Earth over millions of years. Published in Nature, the study involved over 500 bromalites, including fossilized feces, vomit, and undigested food, from the Polish Basin in Central Europe. By reconstructing ancient food webs, researchers unraveled the evolutionary and ecological processes that enabled dinosaurs to rise to prominence during the Late Triassic period, approximately 200 million years ago.
Led by Martin Qvarnström of Uppsala University, an international team used advanced techniques, including synchrotron microtomography and chemical analyses, to examine the contents of bromalites. These analyses revealed well-preserved remains of fish, insects, plants, and even chewed bones. Remarkably, some insect remains were preserved in exquisite detail, with antennae and legs intact. These findings allowed researchers to piece together “who ate whom” in these ancient ecosystems, providing a comprehensive view of the interactions between species.
The study highlighted how dietary diversity and adaptability were critical for the success of early dinosaurs. One notable example is Silesaurus, a small omnivorous dinosaur ancestor weighing about 15 kilograms. Unlike its larger herbivorous contemporaries, such as the Dicynodonts, Silesaurus thrived by consuming a variety of food, including insects, fish, and plants. This dietary flexibility gave it an advantage during environmental changes, such as the Carnian Pluvial Episode, a period of increased rainfall that led to the proliferation of new vegetation. While larger herbivorous reptiles struggled to adapt to the changing plant life, dinosaurs like Silesaurus and their long-necked descendants, including sauropods, flourished by exploiting these new resources.
The findings also demonstrated that over the 30 million years leading up to the Jurassic period, dinosaurs and their ancestors increased significantly in size and dietary variety. Bromalites from later periods contained larger quantities of diverse plant materials, indicating that dinosaurs evolved to consume a broader range of vegetation. This shift not only supported the growth of plant-eating dinosaurs but also enabled the rise of larger carnivores that preyed on them.
The study supports the idea that the rise of dinosaurs was driven by a combination of factors. One theory suggests that dinosaurs’ evolutionary adaptations, such as upright posture and omnivorous diets, helped them outcompete rivals. Another posits that environmental upheavals, like volcanic activity and climate change, created openings by wiping out dominant species. The researchers propose a hybrid explanation: dinosaurs capitalized on their adaptability to take advantage of opportunities created by environmental changes, such as the extinction of competitors.
The research team’s findings also address broader questions about the global patterns of dinosaur evolution. While this study focused on fossils from the northern regions of the supercontinent Pangea, researchers plan to apply their methods to southern regions, where dinosaurs are believed to have first evolved. This approach could reveal whether similar ecological and evolutionary dynamics occurred in other parts of the world.
In addition to providing insights into ancient ecosystems, the study underscores the importance of understanding how species respond to environmental changes. According to the researchers, the adaptability of early dinosaurs offers valuable lessons for understanding life’s resilience in the face of climate change and mass extinctions.
“This work shows how seemingly unremarkable fossils like bromalites can yield remarkable insights,” Qvarnström said. The research demonstrates that dinosaurs’ success was not the result of a single factor but a complex interplay of dietary adaptability, environmental changes, and evolutionary advantages. As Qvarnström noted, “The rise of dinosaurs took a long time, and it was really complex.”
Future studies aim to expand these findings by exploring bromalites from other regions and investigating how dietary and ecological patterns may have varied across the ancient world. This research not only enhances our understanding of the origins of dinosaurs but also provides a framework for studying how species adapt and evolve in response to environmental challenges.
